About the only thing we curse more than our sled breaking down in the backcountry, miles from the truck, is the weather.
It seems the weatherman never gets it right, which is why he (or she) becomes the verbal punching bag for those of us who love to snowmobile and pray for snow. We’re the ones standing in the front yard looking skyward for any sign of a snowflake while our neighbors are packing to head south to warmer climates.
On top of that we don’t want to have to learn about the adiabatic process or altocumulus or centripetal force or drought (definitely not that one—it’s taboo), equilibrium vapor pressure or geostrophic wind or isobars or nacreous clouds or rime ice or tropopause or virga or, well you get the picture.
We just care about two of the most important weather terms ever uttered: cold and snow.
We say bring it on.
But to be fair, we decided to talk to a weather professional and get the low down on winter weather. We posed several questions to Brian Carrington, a former weather forecaster at ABC affiliate KIFI Channel 8 in Idaho Falls, ID, where he worked for two years before moving to Idaho’s Treasure Valley. While at KIFI, Carrington was honored by the Idaho Press Club as having “The Best Weathercast in Eastern Idaho in 2006.”
He tackled all our questions with ease (and a lot of patience we suspect), so here goes.
Does snow really lose its moisture content when the temps get real cold?
Yes. The coldest weather is almost always associated with very high pressure and very dry air.
Throughout the atmosphere, moisture is continually trying to balance itself out. So, if you have a dry air mass in contact with a moist snow layer, the snow will evaporate.
Can it ever be too cold to snow? What is the magic temperature when it’s too cold to snow?
Negative 495 degrees. That is absolute zero—that’s when molecular motion stops.
Can that happen? No. The coldest temp on the planet is not near that.
However, when we have our coldest temps is when we’re under high pressure and dry conditions.
The thickest snowfall (or best) is when temps are near freezing, whereas the colder it gets, they go from snowflakes to falling ice crystals because what happens is when it’s cold the ice crystals can’t adhere to each other as easily—like when it’s warm. When it’s warmer they aggragate, which means they clump together easier.
It’s not so much a function of temperature as it is the presence of a storm/moisture.
How can it snow when it’s above 32 degrees F? (see figure 3)
Although the layer of air we are standing in is above freezing (32 degrees F), the air mass above us is cold enough to produce snow. As long as the warmer surface air layer is shallow enough, the snowflakes won’t have enough time to melt before reaching our tongue. (They will be huge flakes in this scenario.)
Why does it snow in the mountains and rain in the valleys sometimes? Is it strictly an issue of temperature?
It is strictly an issue of temperature because that’s what dictates whether it’s snow or rain. However, under inversion conditions, the higher the elevation, the cooler the temperature. It’s called environmental lapse rate … the air temperature drops an average of 3.5 degrees F for every 1000 feet gained in elevation/altitude.
Can/do mountains create their own weather systems?
Yes, by all means. Mountains can provide the lifting mechanism to promote cloud and storm development.
The Rocky Mountains can create their own low pressure system on the eastern side…that creates an upslope flow, which is the culprit behind many of the blizzards in the Denver and Front Range areas (provided there is moisture feeding in from the south).
Upper air flow over the Rockies produces a wave that in turn will form a counter clockwise formation, i.e., area of low pressure.
Where do Idaho’s storms come from? Or for that matter, where do any of the western states’ storms come from? (see figure 2)
Typically they originate from the Gulf of Alaska. Depending on how far south they go first before they make landfall, the storms are able to tap into moisture from the south.
Warmer water—heated by the sun’s rays—evaporates more so when it taps into a moist, more southerly air mass, it will yield more snow.
Colder air doesn’t hold moisture as well as warmer air. So, when a storm travels south before making landfall, it will be able to tap into the warmer, moist air masses off the California coast, bringing heavy snow to the Sierras and then to the Intermountain West and Rockies—usually in spring and fall. In contrast, mid winter storms usually move in from the north and will be cold and much drier, yielding light, fluffy snow.
Our best snow-making storms come from the west or southwest.
For the most part, all western storms come from the Aleutian Islands/Gulf of Alaska. The closer to the moisture source you are, the more snow you can expect.
What makes predicting storms, snowfall, etc., so tricky in the mountains?
The variability of terrain. The mountains trap air masses of different temps. Mountains redirect the flow of winds. The mountains are really many microclimates right next to each other.
Why is it that one mountain range gets more snow than the one next to it?
Proximity to the moisture source, i.e., generally speaking the coastal ranges will have snow pack depths in the 15-20 feet range while the Rockies will be have snow pack depths less than 10 feet.
Wind can also add or take away snowfall amounts. It’s amazing to be climbing up something steep and deep, with the throttle pinned, get to the top and have to avoid rocks that are only a few inches tall because the wind won’t let the snow settle there. That can happen on the sides of hills as well where a valley can act to channel the wind and snow away. Slopes with more trees on them will slow the wind down and hold more snow. That’s why boondocking is so fun—it’s always deep in the trees.
Elevation and mountain orientation also come into play, that is, the angle of the mountains to approaching storms (see drawing). We generally think of mountain ranges as going north/south but there are some that go east/west.
Weather wise, can you explain the major differences for western states? (see figure 1)
A marine climate heavily influenced by the ocean—the Cascades, Washington, Oregon, northern California to San Francisco. Many of those places have lower elevations but lots of snow. However, the snow is very heavy and settles quickly, therefore we hear the term “Sierra Cement.” Hard to complain about a 6-foot powder day.
Then comes a semi-arid environment in the Great Basin—an area between the Cascades and Rockies. Drier snow and not as much per given storm. Higher elevation means cooler temperatures yielding light, fluffy snow, “Champaign Powder.” Makes early season off-trial rides risky but once a base sets up, the snow will remain a powdery consistency longer.
Why do storm systems “dry out” as they move inland? On the flip side, we hear about how some storms gather strength as they move inland. How does that happen?
They dry out because they expend their moisture as they go. They can build when there are storm-enhancing influences, such as a mountain range or warm, moist air moving in from the south to re-energize it or cold air colliding into it from the northern Plains/Canada.
Can you explain how technologically advanced meteorology is these days and some of the equipment used to predict weather?
Observations have improved. There are more stations and reports are given more frequently.
There aren’t as many weather observation stations in the West compared to, say, the Midwest.
Computers and satellites have made a big difference. Computers help to analyze and predict weather events using complicated models that would take a human days to calculate.
Computer models can blow it. Many times the model will indicate one thing and I will forecast another because I recognize a similar pattern from before and am also able to take into consideration the smaller scale impacts of the local terrain.
Satellites are giving us more accurate, more precise images of our surface and atmosphere. Our five-day forecasts are about as accurate as our two-day forecasts were 15-20 years ago. Honestly, beyond two-day forecasts, accuracy drops significantly.
The Internet has opened the door to let any snowmobiler become his own forecaster.
My biggest competitor is the Internet.
Where would you recommend we go to/look at as the best source of weather information?
Me, of course—just kidding. Go to a local forecaster. He/she will always be better than the national forecasts that just broad brush it.
The National Weather Service is an excellent resource. We work closely with the NWS. Our common goal is to protect life and property.
Before a snowmobile trip a great source is the local avalanche forecast office. It is looking at the weather through the eyes of a backcountry user. Many have forecast discussions and snowfall totals along with avalanche advisories.
One of my favorite sites for the eastern Idaho, western Wyoming area is: www.islandparksnow.net. A great place to start as well is www.avalanche.org.
Any recommendations on what snowmobilers can do to be better prepared for winter conditions?
Have an idea what to expect. Day and night temperature extremes and approaching storms should always be considered. An easy trap to fall into is going out while the weather is good and having a storm move in on your way back. Most of the people reading this are experienced and already know this but it can be near impossible to find your way back when a storm is dropping visibility to nil and covering up your tracks. If you suspect a storm or high winds, stay below the tree line and don’t get too far away from your truck even if you know the area well.
On a side note, one windy day in Idaho (big surprise) I was going to show a couple of friends an epic riding area near a place called Kilgore. The wind was howling and it was snowing, which made for a visibility of about five feet. We were a little spooked when we got to the trailhead since we had come within about two inches of running over a guy in the middle of the road who was working on his sled (his helmet was on and he never even saw or heard us over the wind). The snow was great but to get to the trees you have to cross a wide valley. After imploding off a 6-foot hidden cornice (couldn’t see anything and now my wrists hurt) my “guiding” confidence was dwindling. After many failed attempts of “I think it’s right over there,” we decided to give up and play on the smaller, tree-filled hills we had found. Other than bouncing over a few stumps and taking forever to find our way back home, we all agreed it was still a great day (as is any day on a sled). Moral of the story is, it doesn’t take much to turn what you think will be a routine ride into a whole new ball game. I see a lot of value in a GPS now.
Hope for the best but plan for the worst. Always equip yourself to survive a harsh night.
What is the biggest fallacy surrounding meteorology?
That we can get it right every time and that we make a ton of money. (I am still trying to figure out a way to get another sled for this winter).
Any predictions for snowfall this winter for the West?
Try the Climate Prediction Center www.cpc.noaa.gov.
About Brian Carrington
Carrington was raised in Colorado and went to college at the University of Colorado where he earned a BS degree in environmental sciences.
It was while he was working to get his pilot’s license during college that his interest in weather began.
His first weather forecasting job was in Vail, CO, on a morning show called Good Morning Vail, which was aired on KVBA Channel 8. From there he went to ABC affiliate KIFI Channel 8 in Idaho Falls, ID, where he worked for two years.
He is married to Amanda, who works as a civil engineer.
Carrington loves to snowmobile and told us the first sled he ever rode was in Keystone, CO, on an Indy 440.
The last sled he rode was a 2002 Summit 800, but the motor blew up above Palisades Reservoir on Poker Peak a winter ago.
He moved to Boise, ID, earlier this year where he works as a sales rep for Snake River Yamaha while also working part-time in Boise forecasting the weather at local affiliates of ABC and CBS.