Great Lakes Snow Cover

April 23rd, 2014 at 11:32 am by under Bill's Blog, Weather

nohrsc great lakes   north american snow cover We’re a week from May and here’s the latest snow cover in the U.P.: 26″ Mohawk and SE of Calumet, 20″ near Houghton, 17″ Munising, 13″ Ishpeming, 11″ Paulding, 10″ Michigamme, 9″ Big Bay, 6″ Newberry, Jacobsville, Marquette (airport), 5″ Ontonagon, Gladstone, 3″ Watersmeet. Snow cover is now at 5.9″ of the Lower 48 states. (click on the images to enlarge – the first is Great Lakes snow cover from NOHRSC, the second is North America snow cover and ice cover from NOAA (still a lot of ice on Lake Superior).  Great Lakes ice cover on 4/22 was 33.9% (the most ever this late in spring).  Ice cover on Weds. 4/23 was at 17.2% on Lake Michigan, 59.5% on Lake Superior, 31% on Lake Huron, 10.2% on Lake Erie and 1% on Lake Ontario.  The GFS says that April ends and May starts cool over much of the Central U.S., including Michigan.  Again, don’t be in a hurry to plant this spring – the threat of frost will probably linger into early May.  Here’s the Michigan Tech. Trail Cam – still looks like mid-winter.  Here’s the ice around Granite Is. in Lake Superior.  Click here for webcams around Upper Michigan and Lake Superior.  Here’s the Snowman Cam from Krupp’s Resort at Twin Lakes – lots of snow left…lots of ice on the lake.   Mt. Bohemia is up to 347″ of snow for the winter – and they’re not done yet.  They will be open for skiing through at least the first weekend of May.  Boyne Mt. is scheduled to be open this coming weekend – one of their longest seasons ever (started on 11/15 – so they are headed toward nearly 6 months of skiing.  Ski Brule is also going to open for at least one more weekend.

Global sea ice extent is now well above average (a significant increase since 2012).  Arctic ice remains below the recent average, but significantly above the level of April 2007/2008Antarctic ice extent continues to set daily records.  The extent is much greater than one year ago, much greater than average (well beyond two standard deviations from the recent average) and it continues a steady climb from the mid 1980s.

97 Responses to “Great Lakes Snow Cover”

  1. kevin.w says:

    I’m not planting anything til Memorial weekend this year at the earliest.

    1. Larry of Hastings, barry co says:

      This may not be a good year to plant anything.

      1. GunLakeDeb says:

        Well, my Stand-up Paddle board will be ready for pickup on Monday. I’ve just about guaranteed it will stay cold through at least July…..LOL!

        1. Larry of Hastings, barry co says:

          LOL…

    2. Steve (N. Moline) says:

      I’ve had to cover garden plants a few weeks into June in the past due to frost threats. The way the weather has been this year has me wondering if this will be one of those years.

  2. Travis (Oakland County) says:

    Nice. Lower Peninsula basically snow-free. Huge change in just a couple weeks.

    1. Michael g (se GR) says:

      Wow! And to think, it’s ONLY late April. Still on track for an above average month like you mentioned a few days back?

  3. peggie says:

    is there supposed to be a meteor shower tonight?

    1. Brian (Grandville) says:

      The lyrid meteor shower peaked yesterday, but can last a few days after. Keep May 24 on your calendar this year for a possible good one.

  4. INDY says:

    BREAKING NEWS APRIL WILL END UP BELOW NORMAL!! rody and I travass will have to go back to the drawing boards on the warm weather Maybe May lets hope!! SPRITE IT UP!!! INDYY!!

    1. Larry of Hastings, barry co says:

      How shocking…and life goes on.

    2. Timothy de Graaf says:

      Why do you insist on making a childish jackass out off yourself? You’re an adult, get yourself together…

  5. Tyler says:

    Let me know what spring and summer are like down there. Those are two seasons in the U.P. that are nonexistant. At least downstate gets a spring and a long hot summer. Winters are mild down there as well.

    1. Larry of Hastings, barry co says:

      I rather be living in the U.P. than here.

    2. Barb says:

      I wouldn’t say this winter has been mild by any means.

  6. Jack says:

    Photo of The Day, from Northern Lights Page.Very Nice lots of Purples . Here :::: http://www.softservenews.com/photos/large/1039605_10201674308523825_1961616445_o.jpg. AWESOME. !! Stay cued……….

  7. Jeremy (Three Rivers) says:

    12Z GFS is getting on board with the snow chances around the first of May. Printing out a few inches TO OUR SOUTH! http://www.instantweathermaps.com/GFS-php/showmap-conussfc.php?run=2014042312&time=PER&var=ASNOWI&hour=216

    1. Jeremy (Three Rivers) says:

      I’d wait a few runs to get worried and the snow wouldn’t accumulate anyway. I can’t remember snow in May, though I’m only 16.

    2. GunLakeDeb says:

      That’s just crazy….. snow in Ohio in May.

    3. Rocky (Rockford) says:

      INCREDIBLE!!!!

    4. Rocky (Rockford) says:

      Be careful Jeremy – you may just be labeled a horrible snow demon for speaking the facts!!!!

      1. matt says:

        Snow and snow storms will be here soon who knew imagine that i love it bring it

      2. Jeremy (Three Rivers) says:

        Thanks.

  8. Florida1993 says:

    Who cares.

  9. Cali1993 says:

    Meanwhile the grass is green and the daffodils are in full bloom here in GR.

  10. So does the severe weather in the plains look to be good for a tornado outbreak? I need to know because I will go chase if it is. So far the weather channel has a 5 for the TOR:CON. Doesn’t seem very high to me. At least not high enough to hint at an outbreak

    1. Or are they keeping numbers lower due to uncertainty?

      1. Larry of Hastings, barry co says:

        50/50 chance.

        1. Cort S. says:

          TOR:CON’s definition:

          The probability of getting a tornado within 50 miles of a given point. That’s a 100-mile diameter circle. So a 5/10 TOR:CON would mean there is a 50% chance of there being a tornado within 50 miles of your location.

          SPC’s tornado probability definition from their severe weather outlooks:

          The probability of getting a tornado within 25 miles of a given point. That’s a 50-mile diameter circle, which is one-fourth the area that TOR:CON uses.

          So on a day like today, SPC has a 5% tornado probability:
          http://www.spc.noaa.gov/products/outlook/day1probotlk_2000_torn.gif

          And since TOR:CON’s area of prediction is four times as large, that’s why Greg Forbes might call today a 2/10 or a 3/10.

    2. Cort S. says:

      There is some uncertainty in how the timing of the large scale ingredients will work out on Saturday, and how the “clean” the setup will be on Sunday. Yesterday’s Euro’s forecast of the large-scale setup this weekend was very similar to the setups of many other big outbreaks in history. But since then, it has trended a bit slower, leading to uncertainty on whether the storms will fire up during the day on Saturday or at night. Sunday has some uncertainty too, due to large-scale uncertainty in the development and vertical structure of the low-pressure system, small-scale uncertainty in any contamination from the convection the night before. Monday is looking good in terms of large-scale ingredients. The chase territory for the area of maximum potential Sunday-Monday won’t be as ideal as out west on Saturday, but it’s workable if you are careful and willing to sacrifice chasing the biggest action areas for the sake of safer chase territory. This setup has big potential, but big bust potential too at least in the sense of seeing large tornadoes. That said, this is probably the best setup for severe storms and tornadoes so far this year, and another one won’t happen after this one for at least a week after.

      1. Cort S. says:

        The run-to-run consistency of the models is still not good, but there is still good potential in the large scale Saturday-Sunday. As usual, the devil is in the details. But since you don’t live in Oklahoma, you’re going to have take a gamble off of the large-scale setup and hope that the details don’t muck it up. And you’re going to need a road map of Oklahoma. And I pray that you have a good data feed out there… it can be pretty spotty in western OK. And if things come together just right, yes, a few tornadoes could be violent.

  11. Rocky (Rockford) says:

    Great job Bill! Keep the facts coming about the cold and snow! I love it!

  12. Rocky (Rockford) says:

    This may be the year with only a few days of hot summer weather! The “mini ice age” is upon us! fixxxer and his merry band of complaining aliases will love that!!!

    1. Cliff(KZOO) says:

      Rocky, even if the mini ice age was upon us, it doesn’t happen overnight.

    2. Larry of Hastings, barry co says:

      What happen to global warming?

      1. Cliff(KZOO) says:

        Err climate change?!?!

      2. Cort S. says:

        Might want to look at the rest of the globe… it’s a big world out there.

        http://www.ncdc.noaa.gov/sotc/service/global/map-blended-mntp/201403.gif

        1. GB says:

          Ha epic burn by Cort on so many levels but not sure the intended audience will get it.

          I’m not a global warming or climate change person truly don’t think anyone knows the truth this includes Bill. I think both sides are just as likely to be right and both sides have bs agendas.

        2. Mike M. says:

          Ooh, big scary red spots. Let’s see what the satellites have to say about March…

          http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_March_2014_v5.png

          Wow. 0.17°C above average. Crank up that AC.

        3. Michael g (se GR) says:

          My side’s agenda is to be left alone. The other sides agenda is to control people’s lives in the name of stopping climate change.

        4. Cort S. says:

          Note that the link that I posted above was not meant to prove global warming / climate change. Certainly, just looking at surface temperature during one month is incapable of doing that.

          The point of my post was to get people to expand their minds! Think bigger. Just slightly! It’s ridiculous that we still have people yucking it up just because the Midwest had a frigid winter and spring. It’s plainly myopic. I’m trying to nudge people toward thinking about bigger spatial and temporal scales… scales that individual humans don’t naturally operate on! Certainly that map I posted does nothing to prove anything about the global climate… it just reminds us to take a step in the right direction and think bigger, at least a little bit. You can argue against climate change, just make sure that you at least have a good argument. The cold weather in the Great Lakes region over the course of several months ain’t a good argument.

          I’m trying to make this blog a place where people can learn something new and think about something beyond their preconceived notions of Red vs. Blue, good vs. bad, us vs. them…

        5. Bill Steffen says:

          You remember the grief I got in March 2012 when I said the same thing.

        6. Cort S. says:

          And I don’t think I was one who gave you grief. It was as obvious then as it is now that the March 2012 heat was a regional thing just as the recent cold weather has been. Really see a lot of baseless arguments (pundits included) whenever the weather gets hot or cold.

        7. Bill Steffen says:

          No…wasn’t you, Cort…didn’t in any way, shape or form mean to imply it was you…in fact, I’ve on MANY occasions over the last few months told people that global temperatures have been a little warmer than average through our cold winter and early spring. Global sea-surface temperatures are warmer than average, too (though they are a little on the cool side along the Gulf of Mexico off Texas and Louisiana, which may have been a minor factor in our slow start to severe weather season).

        8. Cort S. says:

          It’s fine, I didn’t think you were, but I tried to exonerate myself anyway.

          It definitely is difficult as a human being not to get snarky whenever your “side” is currently perceived by the populace to be “winning” or “losing.” Not that I really like the idea of “sides” anyway. The binary competing perspectives that our media feed us and that our psychology prefers to think in terms of just don’t satisfy an attempt to understand all the complexity in the world.

        9. whatBillwantstosaybutcant says:

          One thing i love about science is, even if you don’t believe in “science”….it’s still true. Science doesn’t have a political agenda or some ancient dogma it has to adhere to, its just the way it is. All data sets need to be looked at and when we see what we think to be a trend we should kinda believe it. Just a thought. Another thing that we can all learn from scientists is, even if there life’s work gets proven other wise, they will embrace that news and except it as fact, and move on! Whats the worst case scenario? We figure out how utilize the nuclear furnace in the sky?

        10. Brian(Grandville) says:

          There it is. THAT is the answer.

        11. Mark (East Lansing) says:

          Cort, you want THIS group to expand their minds? And I thought I was an optimist? :-)

      3. Larry of Hastings, barry co says:

        I want it to warm-up and not get cold again.

      4. Brian(Grandville) says:

        It has never occurred.

        1. Cliff(KZOO) says:

          I blame the sun!!! No but seriously this all is quite laughable, all the money that gets pushed around on the topic of global warming/climate change now is unreal.

  13. Dikehopper (Fennville) says:

    This is quite off-topic, but I think that most of you with kids (or who once were kids) will enjoy this – especially the Comments section: http://ricochet.com/americas-war-kids/

    1. Jack says:

      Thanks, Interesting Read !! Wahoo ” Wiffle Ball” Loved Playing That when I was Kid. ” Many,many, Moons Ago”!!!! Stay CueDD…KIDS!!! ;-)

    2. GunLakeDeb says:

      Having raised 7 kids, I LOVE the sounds of kids having fun; and know for a fact that the “gang” I ran with as a kid made a LOT of noise….LOL!

  14. Jack says:

    ” CLIMATE CHANGE”???????????? NOT!!!!!!!! STAY CUED and Good To Have Ya BACK BILL ! U DAH BEST!! Keep The Great WORK…” Rolling”"”" ( pun intended ). ;-)

    1. Rocky (Rockford) says:

      +100 trillion, gazillion!

    2. Cort S. says:

      A pretty easy mistake to make. But don’t worry, we’re learning.

      The weather that happens in your 0.05% of the globe (Michigan) over a period of months does not necessarily represent the climate of the globe over a period of decades. I have been enjoying above-normal temperatures in Utah ever since February. It would be equally foolish for me to say that the warm weather here proves global warming.

      1. GunLakeDeb says:

        I DID hear someone on the Weather Channel say (referencing Earth Day) “We’ve GOT to stop Climate Change!!”

        I just burst out laughing – now THAT is a tall order: to stop something that’s been occurring for eons….. but you’re right. Just because it’s warm at point X or cold at point Y doesn’t indicate what the “climate” is doing. And yes, Cort, of all the places to be this winter – you sure picked a good one!

        1. Brian(Grandville) says:

          I’m not sure what they (TWC) recommend we the (U.S.) do to stop their theory. We’ve done more than most all countries in the world to reduce emissions and reduce our dependency on fossil fuels. Yet, we still are to blame. If they think that if we all buy a Prius and plant a tree, that it is going to help reverse “climate change”, then good luck, and wishful thinking. They seem to base all their climatology on the past 20 years.

        2. whatBillwantstosaybutcant says:

          Do you realize ONE 747 pretty much going anywhere a 747 would normally fly takes off with about 58,000 gal. of kerosene on board? 58,000. Do you know how many 747,777,737,A330,A340,A380 etc,etc,etc flew just today? Thousands. Along with all of the vehicular traffic driven world wide daily? If we don’t think maybe, just maybe, us taking all of that long chain hydrocarbon out of the ground that took millions, yes i said millions, and burn it in basically the blink of an eye, we aren’t disrupting some balance? You are probably not wired upstairs to grasp much more than just day to day mundane tasks.

        3. Irish coffee says:

          There are plenty of Amish folks living in this country who leave barely a fingerprint of carbon, let alone a FOOTPRINT! They quietly go about their business/lives w/o drawing attention to their eco-friendly ways & do not demand others’ live as they do.Elitist liberals will continue to holler and shout=- “the sky is FALLING” while taking full hypocritical advantage of power/electric/energy instead of quietly leading by example…. $.02 carbon for thought

      2. GB says:

        Love this guy. Cort should have his own blog.

  15. SlimJim NW GR (1) says:

    While Munising very well have 17” of snow in their area in town there now is a lot of bare ground (as well as there should be on April 23rd)

    http://www.exploremunising.com/web-cams/

    There is now also a lot of bare ground in Houghton as well (also as there should be)

    http://www.mtu.edu/webcams/
    SlimJim

    1. Bill Steffen says:

      There is a big difference between areas near the shore (where there is very little snow right now) and woodsy inland areas at higher elevations where the snow depths are taken for Grand Marais, Munising and Marquette. I’ve seen Marquette downtown with a trace and the airport with 20″.

      1. Tyler says:

        Marquette is down to nothing except lots of snowpiles around. You go south of Marquette to Trenary and they still have lots of snow in the wooded shaded areas at least a foot but they have bare ground where the sun hits. We still have some snowpiles left here in Escanaba but they are getting less and less. Last year we had snow cover till about the 21st of April here and the year prior to that it was completely gone by Mid March.

  16. Thanks Cort. We would head out Friday if things look promising. It would be a drive straight through all the way to OK. I’m still Leary as to if its a good time to go. If you put a bet on it, does it look like a good one to go chase? I know it’s taking a gamble but what’s your thoughts? Just trying to get feedback on if we should or not

    1. Brian(Grandville) says:

      Kyle, are you leaving Friday to chase on Saturday. If so, keep in mind you will have to travel through parts of Chicago, and St. Louis. There is not really a good time to drive through those cities on Friday.

      Years ago I left for Las Vegas on a Thursday morning at 8 a.m., and made it to Joplin at 7 p.m., in little traffic. That night there were tornadoes in Amarillo TX. I saw some of the damage on the way through the next day. The day after that the Greensburg tornado hit.

      1. Still uncertain whether we are going yet or not but yes we would leave Friday. Traffic could be an issue. The only thing that hold me back is the uncertainty and low torcon

      2. Larry of Hastings, barry co says:

        What kind of equipment will you have in your vehicle when you go storm chasing?

    2. Cort S. says:

      I think your chance of seeing a storm of any type Saturday+Sunday is higher than seeing no storms at all. You would have a decent chance of seeing strong or severe storms, but I also worry about the decent chance that you’ll get caught up in a murky multicellular system and get into trouble with hail or heavy rain, especially if you don’t have radar. But you’ve probably assumed that risk long ago. This setup looks pretty promising to be an exciting one. Could be one of the better setups this spring.

      I also expect the roads in western OK to be dotted with chasers and chaser convergences everywhere you go. It’s astounding how many chasers there are out there. It’ll be a weekend and the first/second big tornado potential of the year. I chased a Moderate Risk near Kingfisher a few years ago and there were chasers everywhere, in every town, on every highway. Chasers of all types: local yokels, local veteran chasers, local meteorologists, nonlocal veteran chasers, meteorology school chase groups, commercial chase tours, media (vehicles and a helicopter), the Dominator… You’ll certainly be in good company.

      Are you planning on staying overnight around Tulsa? A bit of comfortable sleep, a nice shower, and some breakfast will really get you prepared for the challenging day. Convective initiation probably won’t happen until at least some time in the afternoon Saturday, so you’ll have time to get to western OK if you leave Tulsa mid-morning. That’s something to think about, as plans might change if the target area/time changes in later forecasts.

      1. Yeah Cort I was planning on possibly somewhere between Tulsa and Oklahoma City. Try and get in that in between spot so if there are changes I can move. But yes I do expect to see lots of storm chasers out there. Might even see Reed Timmer! as I know he is in Oklahoma tonight chasing. I hear he got caught up in some golfball-tennis ball size hail near Hollis, OK. I will wait for another run of the models and latest synopsis from the NWS. I appreciate your analysis, its nice to have someone that knows a lot about severe weather and tornadoes. But yeah we will likely get a hotel somewhere around Tulsa or a little west (Maybe Bristow or Chandler).

        1. As well as Cort, do you think that in the Day 3 they may issue a Moderate Risk area for this event? Seem’s reasonable to me.

        2. Cort S. says:

          I don’t think they’ll go moderate until Day 2.

  17. Rocky (Rockford) says:

    Bring on the “mini ice age”!

    1. Larry of Hastings, barry co says:

      I want global warming, I want to sweat and complain about the hot temperature. LOL

    2. Jeremy (Three Rivers) says:

      Iceagenow.info would be the site for you… Give it a click, they’re all snow crazy cold lovers like you. :)

  18. Jack says:

    OFF TOPIC..Re SPORTS ::: Detroit Lions running back Montell Owens, center, runs through drills at the NFL football team’s training facility in Allen Park, Mich., Tuesday, April 22, 2014. (AP Photo/Carlos Osorio)
    ALLEN PARK, Mich. (AP) — The Detroit Lions will open the season with a home Monday night game against the New York Giants.

    The Lions announced their 2014 schedule Wednesday night. The Sept. 8 game against the Giants will mark the first time Detroit begins the season in prime time since 1991, when the Lions opened with a Sunday night game at Washington. The last time Detroit opened on Monday night was in 1971 against Minnesota.

    In week 5, former head coach Jim Schwartz will return to Detroit as defensive coordinator for the Buffalo Bills.

    The Lions will play the Atlanta Falcons in London on Oct. 26 as part of the NFL’s International Series.

    Detroit will host the Chicago Bears in the Lions’ annual Thanksgiving game. It will be the 16th Thanksgiving meeting between the Lions and Bears.

    The complete Lions schedule:

    Sept. 8 N.Y. Giants, 7:10 p.m.
    Sept. 14 at Carolina, 1 p.m.
    Sept. 21 Green Bay, 1 p.m.
    Sept. 28 at N.Y. Jets, 1 p.m.
    Oct. 5 Buffalo, 1 p.m.
    Oct. 12 at Minnesota, 1 p.m.
    Oct. 19 New Orleans, 1 p.m.
    Oct. 26 at Atlanta (London), 9:30 a.m.
    Nov. 2 BYE
    Nov. 9 Miami, 1 p.m.
    Nov. 16 at Arizona, 4:25 p.m.
    Nov. 23 at New England, 1 p.m.
    Nov. 27 Chicago, 12:30 p.m.
    Dec. 7 Tampa Bay, 1 p.m.
    Dec. 14 Minnesota, 1 p.m.
    Dec. 21 at Chicago, 1 p.m.
    Dec. 28 at Green Bay, 1 p.m.
    —–

    Online:

    The Lions’ schedule

    Share this:
    Email
    Print
    Twitter7
    Facebook
    Google
    Reddit

    1. Brian (Grandville) says:

      Thanks for the schedule Jack, forgot it was out today. I’ll make an early prediction that they go 9-7, but some how miss the playoffs again. Its just not easy to get excited about them, after so many bad years.

    2. Larry of Hastings, barry co says:

      GO LIONS…SUPER BOWL CHAMPS. GO TIGERS…WORLD SERIES CHAMPS 2014. GO RED WING…CHAMP 2014. All things are possible, when you believe. Good night and sweet dreams.

    3. Mark (East Lansing) says:

      PLUS – the Tigers will be hosting the Royals right across the street at the same time as the MNF game. Party time, Detroit style!

    4. Ned S. (East of Holland) says:

      Thanks for the info. Jack. Looks like a tough schedule for the Lions, especially the last two games away against division rivals.

    5. Irish coffee says:

      Schwartz- LOL….Difference between the Lions vs. good NFL teams? Lions hire coordinators to become HEAD coach, while winning teams hire DET head coaches to become assistants/equip. managers! ;)

  19. Barb says:

    Does anyone know if there is snow just east of Cheboygan along US 23? I’m heading up to my cottage this weekend for a meeting and wondered what I could expect.

    1. Jack says:

      Try this Link Barb… forecast.weather.gov/MapClick.php?zoneid=MIZ017. Have fun & Be Safe, and as always..Stay CueDD.

  20. John (Norton Shores) says:

    Sad night for the Muskegon area! Prayers going out to the family and friends of that young student shot and killed in Muskegon Heights tonight. Sorry it’s off topic but it sure is very sad.

    1. Brian(Grandville) says:

      Someone made a comment on the story about “if you don’t think there’s a problem, then you’re part of it”. I couldn’t agree more. Why so much violence between these young men?

  21. Jack says:

    Good THERAPUTIC Thursday To ALL…. On April 24 in Southwest Lower Michigan…

    4/24/1980
    Only two days after setting record highs in the 80s, a record snowfall blankets Lower Michigan. Grand Rapids sets a record for the date with 2.4 inches of snow, after hitting 86 degrees on the 22nd. Who Knew?? Lol…stay CueDD……………… ;-)

  22. Jack says:

    Here is A Old Guess Who Tune That Should Be THERAPUTIC for All on BILL’s BLOG…..CUE ::: http://www.youtube.com/watch?v=MXyXDuI9p5U. Stay Cued & Share The LAND….. :-)

  23. Tyler says:

    This year has to be the coldest calendar year that I can remember. Even last year we really warmed up the last week of April but it took till then. The only other years in my lifetime that can rival this year were 1996 and 1997. Both severe winters and lots of snow along with a cold spring.

  24. Jack says:

    Segue Into :::: Ten Years After – Year 3,000 Blues (HQ/Lyrics) – YouTube
    ► 2:33► 2:33
    http://www.youtube.com/watch?v=rJMMO3lllww

    1. Bill Steffen says:

      Great song…I head Alvin Lee/Ten Years After live back in the 70s. Sad that he’s “Goin’ Home”.

  25. Dan (Byron Center) says:

    Is it too much to ask for 60 degree temps to stick around for more than a day or two? I’m trying to get our soccet team going this spring. We have froze at our practices and our game. Any decent warm up tjat will stay around coming our way?

  26. Dan (Byron Center) says:

    *soccer

Leave a Reply