Eastern Powder: Add Snow Ridge to the List

Whenever I need material for a blog post, I find it helpful to turn to Unofficial Networks for either a bogus seasonal forecast or a top-10 list that I can quibble with.

Todays offering, served up via Twitter, is their top-10 list for scoring powder in the east.

#SkiTheEast | #UnofficialNetworks https://t.co/zVePWMiI92

— UnofficialNetworks (@UnofficialNet) October 5, 2016

Truth be told, there's not too much to complain about the resorts on this list, although I'm not sure I would have picked Whiteface, even though I loved skiing there as a kid.  It was nice to see Plattekill make the list as back in the day I provided forecasts for them and found it to be a nice family run place with decent snow by eastern standards.  

There is, however, one very important omission, and that is Snow Ridge Ski Area.  Snow Ridge is on the Tug Hill Plateau, which is well known for extreme snowfall.  The ski area advertises an average snowfall of 230 inches, and that's probably fairly close to reality.  A nearby climate station in Boonville, New York, averages 210.

Approximately two-thirds of this snowfall is lake effect and typically of high quality and low density.  In fact, the average water content of snow downstream of Lake Ontario is lower than that of Utah.  All snow is not created equal.  In the east, many storms produce heavy or upside-down snowfalls.  Much of what falls at Snow Ridge is high quality (ditto for Mount Bohemia in northern Michigan).

And, if you want to play the odds, the snowfall climatology at Snow Ridge exhibits a pronounced peak in December and January, with average monthly snowfalls of 46 and 52 inches at the nearby Boonville climate station. For comparison, Berthoud Pass, Colorado, a relatively snowy high-altitude pass near Winter Park, averages 51 and 50 in those months.

Oh yes, you can badmouth the limited vertical at Snow Ridge (500 feet), but there's a hill there and some damn good snow.  Let's give Snow Ridge some props!

Snow Ridge Ski Area

Wasatch Snow, Eastern Apprehension

A beautiful fall sunrise over Salt Lake City

Salt Lakers were treated to a beautiful fall sunrise and crystal clear skies.  Days like this you just have to take a deep breath and suck it all in.  

A quick look at the mountains reveals a new white frosting.  Data from Alta-Collins is AWOL this morning, but the NWS reports about 5 inches fell yesterday in the Town of Alta.  I'm not sure it looks like that much in weather cams, but I did notice that Alta is making snow or at least testing their snow gun near the Albion base.  Get up there now for first scratches.  

Source: Alta.com

Overnight forecasts for the rest of the week are a bit disappointing if you want more snow, but encouraging if you are in the snow-safety industry.  The latest NAM, for example, keeps us cool, but even with the next trough pushing through, brings us just some scattered snow showers and little in the way of well-organized precipitation.  

Now that fall is upon us, I'm starting to look at the downscaled Short Range Ensemble Forecast system products that we put together this summer.  We have no idea if these are good or reliable, but this is a blog, so I'll go with them anyway.  There are 26 members in this ensemble, which is run at 16-km grid spacing, but we downscale that to higher resolution.  All but 3 downscaled members produce 0.4 inches of water equivalent or less for the rest of the week at Alta.  There are a couple that go bigger than this, so one can't rule out a larger storm, but the odds are low.  

As I mentioned above, this is good news if you are in the snow-safety industry.  If we're not going to go huge and start building up a snowpack, early snow almost always turns to weak snow when the inevitable ridge returns during the fall.  Better for us to have just a little snow this week and melt or sublimate most if it away rather than have a couple of feet of snow facet and rot before the next storm.  Let's stay dry until the end of the month and then open the spigot.

Meanwhile to the East, Hurricane Matthew is currently an extremely dangerous storm that will likely impact the entire eastern seaboard of the U.S.

As of 6 AM MDT, Matthew had just made landfall over Haiti as Category 4 hurricane with maximum sustained winds of 145 mph.  Wind, storm surge, and rain, which is expected to be in the 15-25 inch range with isolated amounts of 40 inches, will unfortunately make this a catastrophic storm for Haiti.
Hurricane warnings are now posted for Cuba and the Bahamas.  Nothing yet for Florida, but the latest forecasts have moved the storm tracks ever closer to the east coast.

The latest GFS forecasts suggests that Matthew will have some impact along the southeast coast in the form of waves, beach erosion, precipitation, and/or wind, and possibly the entire eastern seaboard all the way to Maine.

Details will, however, depend on track, timing, intensity, etc. that can't be nailed down this far in advance.  Pay attention to official forecasts from the National Hurricane Center and National Weather Service.  

Lightning then Snow

Thunderstorms yesterday and especially overnight made for some great entertainment and a nice prelude to the major weather change that is currently underway.  Cloud-to-ground lightning strikes detected by lightningmaps.org shows that both the Salt Lake and Utah Valleys got their share.  Stike densities were, however, much higher along a corridor extending from roughly Park City to near Evanston.

Source: lightningmaps.org

Temperatures dropped significantly overnight at all elevations.  Observations from the University of Utah show a somewhat stair-step like descent from a high yesterday in the high 70s to the current temperature of 44ºF.

Source: MesoWest

In the mountains, temperatures at Alta-Guard reached almost 60ºF, but this morning sit at a much more pleasant 27ºF.  Looks like the magic threshold for precipitation to change over to snow as crossed around 5 am MDT.

Source: MesoWest

Snowcams show the ground is once again white.

Source: Alta

I was planning on giving the Utah Golf team a special award for bravery this morning, but learned they are now in a weather delay until 1 PM.  Golfers are not all that tough after all.  

A little snow won't slow us down! We are officially underway! #GoUtes ❄️☃️⛳️ pic.twitter.com/9Ob5SyFZoV

— Utah Mens Golf (@UtesGolf) October 3, 2016

Looks like valley showers and mountain snow showers for today, especially the next couple of hours.  Enjoy!   

Tropical in the East, Late Fall in Utah

This morning, it's worth taking a step back and looking at the "Supernational" view of the GFS 50-mb height, precipitation, and cloud forecast for today through Friday morning.

Let's begin in the east where the big story is Hurricane Matthew, which is currently a major hurricane (category 4) with sustained winds to 140 mph.  In the loop above, the 500-mb low associated with Matthew moves into the picture on Monday when it is expected to be affecting Jamaica and Haiti. Beyond wind and storm surge, the National Hurricane Center is calling for total rainfall accumulations of 15 to 25 inches in Haiti, with local accumulations of up to 40 inches.

Matthew is a slow moving storm presently, but is expected to accelerate as it moves northward.  Most models and ensemble members call for it to move northward near or east of the US East Coast.  It is worth paying close attention to forecasts over the next few days if you live along the eastern seaboard or are planning to travel there.

Moving back west, tonight marks an abrupt change and we can expect the work week to bring the coldest stretch of weather we have seen in a long time to northern Utah as a series of troughs moves through the state.  Forecast 700-mb (10,000 ft) temperatures for 6 AM tomorrow morning through 6 PM Thursday are between about -7ºC and -3ºC, closer to the averages for late October and early November, so consider this a practice run for the late fall.

And yes Virginia, there will be periods of snow in the mountains.  Looking at the latest model runs, there don't appear to be any huge storms on tap and it is likely that by the end of the lake we will see a Purgatory-like snowpack.  Not enough snow to ski and too much to hike.  Of course, I saw video of many people skiing after the last storm, so perhaps my standards are too high and there's always the hope that we come in on the high side (or above) projections.  This is a pattern with a wide range of possibilities, so perhaps northern Utah skiers should pay attention to forecasts too.

Personally, I think it's too early for these sorts of storms.  Better to hold off until later in the month or early November and then open the spigot.  Early snow frequently turns into weak snow when the inevitable fall ridge returns.

Weather Observations on the Salt Flats

The Bonneville Salt Flats, a remarkable geological wonder, in July 2008

The Bonneville Salt Flats are a remarkable geological wonder and well worth a visit and a hike of a nearby mountain.  Most people drive through them at a high rate of speed trying to get to Nevada or California as quickly as possible, but even a quick stop reveals a world completely different than any other you have experienced.

The Bonneville Salt Flats are perhaps best known for land-speed events that take place on the hard salt crust to the northeast of Wendover.  In recent years, however, that salt crust has thinned and degraded, forcing cancellations or restrictions in speed events and sparking controversy concerning management of the salt flats.

Brenda Bowen, a professor of Geology and Geophysics and director of the Global Change and Sustainability Center at the University of Utah, is leading a 3-year study to improve understanding of the Salt Flats and their recent change (see this Scientific American article for more information).  Yesterday, some intrepid members of our MesoWest team installed a weather station on the Salt Flats to help with the effort, and returned with some great photos.

These photos illustrate the highly dynamic nature of the Salt Flats.  It's not uncommon for portions of the salt flats to be covered with water, but thanks to recent storms, the coverage and depth is quite high.

Click here to access weather observations from the station.

Are Recent Bad Snow Years at Alta Due to Climate Change?

Since the 2010/11 ski season, the Wasatch Range has experienced below average snowfall years.  Data from the Utah Avalanche Center shows an average seasonal (October-April) snowfall at Alta of 497 inches since 1945/45, but over the last five seasons we've received only 330, 383, 358, 268, and 393 inches.  

I am often asked if these poor snowfall years are due to climate change.  

The answer is no.  

Many people are surprised to hear this, but here's why I do not think the recent poor snowfall years at Alta are due to climate change.  

First, the base of Alta is at 8500 feet, well above the freezing levels of most storms during the winter.  While it is possible that you can experience a brief rain-on-snow or drizzle-on-snow event at Alta, nearly all of the precipitation that falls there during the cool season falls as snow.  The low numbers over the past five years are not due to more wintertime precipitation falling as rain, but instead less precipitation.

Second, at that elevation, the fraction of precipitation that falls as snow during the cool season is relatively insensitive to another 1ºC (about 1.8ºF) of warming.  The image below from my book Secrets of the Greatest Snow on Earth and based on work by Leigh Sturges and John Horel here at the University of Utah shows the percentage of snow that currently falls as snow that would instead fall as rain if the climate were 1, 2, 3, or 4ºC or warming.  Alta is blessed with high altitude and thus snowfall at that elevation is less sensitive to the first couple of degrees of warming.  

Percentage of snow that would instead fall as rain with 1, 2, 3, and 4ºC of warming

Third, we're not really sure if the cool-season precipitation in northern Utah will increase or decrease with global warming.  Some model projections suggest we'll be drier, others wetter.  For all future emissions scenarios most climate models lean to a wetter future (the blue color bars below indicate the average winter precipitation change amongst models, the whiskers the middle 50% of the projections, and the dots the middle 80%).  Bottom line is that at present there isn't a strong reason to expect global warming to cause a decrease in wintertime precipitation, although it can't be ruled out.  

Projected seasonal and annual precipitation change over the central Wasatch and surrounding region for the 30-year periods centered on 2040 (2026–2055), 2060 (2046–2075), and 2085 (2070–2099) relative to 1976-2005.  See Fig. 6 for emissions scenarios.  Winter is December through February, Spring is March through May, Summer is June through August, and Fall is September through October.  Bars show the average change across the model runs, whiskers the range between the 25th and 75th percentile of the model runs, and dots the range between the 10th and 90th percentile of the model runs. Source: http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html

Instead, I see the recent poor snow years at Alta as largely a reflection of climate variability instead of climate change.  Shifts between wet and dry periods are evident in both the instrumented and paleoclimate (e.g., tree ring) records.  The causes for these shifts are not well understood and I hesitate to speculate as to the causes of recent poor snow years, but my view is that the climate-variability dice simply have not rolled in our favor the past five seasons.

That being said...

This analysis is for Alta, a high elevation site in the Wasatch Range.  It does not mean that climate change is not influencing snowfall and snowpack at lower elevations (e.g., base of PCMR, Mountain Dell, etc.) or that Alta and the upper elevations of the Wasatch will not suffer pain and agony in the future.  It also doesn't mean that it isn't getting warmer in Utah (it is).  Different snow and climate measures (e.g., temperature, snowfall, snowpack, etc.) respond differently to climate change depending on elevation, aspect, and regional and local climate (for example, see Western Snow Trends and Global Warming: Part I and Part II).   When it comes to snow, we simply need to be careful about generalizing across all climates, elevations, and aspects, and cautious about conflating climate variability with climate change.  

Postscript:

Shortly after posting this article, I remember I've written about this topic previously.  See Is This a Long-Term Trend.