WINTER SPORTS — The calendar says its spring, but the snow keeps piling up in the mountains, inviting skiers, snowshoers and snowmobilers into continue their winter ways.
Go in a group, keep track of the weather and use your best winter travel sense – because you’ll pretty much be out there on your own. Despite more layers of new snow this week, most of the region’s downhill ski areas will close for the season on Sunday.
And the Idaho Panhandle Avalanche Center has stopped testing the snowpack and posting weekly avalanche advisories.
Kevin Davis, IPAC director, posted a summary of spring snow travel tips to help snow goers make good decisions on their routes through spring snow conditions.
“With a better than average snowpack we should be doing well on mountain travel until late June in places,” he said.
SPRING TRAVEL TIPS
By Kevin Davis, Idaho Panhandle Avalanche Center
Spring is generally a safe time to travel in the mountains but there are some rules to live by. The safest and best conditions will exist after a good nighttime freeze.
Dig a pit to see how deeply the freeze penetrated. This will give you an idea of how quickly the snow will become slushy and unstable.
Get on the slopes early before the temperatures get too warm or the sun gets too intense. Mountain temperatures above 50 degrees should be an indicator that conditions are becoming unstable. Strong radiation can penetrate deep into the pack and destabilize weak layers.
Steep south facing slopes are affected most rapidly by strong sun. If you are into the slush up to your boots or you’re laying on the throttle to move its time to get off the slope.
By planning your route to take you to slopes just as they come into the sun and begin to thaw you can enjoy good, safe sliding.
Always be careful around rock outcroppings because they hold heat and weaken the snow for some distance around them.
Rain always weakens the snow pack and this time of year rain can lubricate ice crusts making the overlying layers more prone to slide.
New snow on an ice crust that is experiencing melting during the day can be extremely unstable, especially if it is wind-loaded.When we do get new snow watch for the type of surface it is bonding to.
In general, new snow will be more sensitive to radiation. Surface hoar can also be a weak layer in the spring so check under the new snow accumulation to make sure you’re not dealing with that little devil.
In steep terrain you may notice glide cracks where a fracture in the snow has opened up, often to the ground. The snow is gradually creeping down hill and stability above and below these areas is highly unpredictable.
Keep track of extended periods of thawing, not only during the day but most importantly overnight. This will also decrease snow stability. Night-time temperatures below freezing are a must for good sliding conditions, and safe sliding conditions. The more nights in a row that freezing conditions occur, the more stable the snow is likely to be. Freezing conditions will usually accompany clear nights while overcast nights tend to trap heat.
SPRING SNOWPACK OBSERVATIONS
In the high country we’re doing great on snowpack with the Northern Panhandle Region at 131%, the Spokane River Basin at 109%, and the Clearwater Basin at 105% of average peak snowpack. March has set records for precipitation, and depending on your point of view, that could be very good, or quite depressing.
If you’re reading this I’m betting your clapping your hands like a little girl that just got a new stuffy. Listen to these Snow Water Equivalent numbers from the last 30 days, Lost Lake – 16”, Lookout Pass – 9”, Schweitzer – 22”, Hidden Lake – 17”, Bear Mountain – 23”. That translates to multiple feet of new snow.
The Climate Prediction Center is showing below average temperatures and above average precipitation for the month of April.
The wind has built up some very large cornices and these will become unstable as the weather warms. Be cautious near ridgelines where wind deposition could be deep on multiple aspects. We have had good overnight freezes so the snowpack is great for traveling today and this weekend.
Winter weather will continue into next week so be thinking about potential slab avalanche conditions with new snow and for a 24 hour period after the storm. Check to see if the new snow is loading up over a layer of surface hoar.
On your ventures into the high country remember to respect old terra firma, the brown stuff, that sticks to your boots and tracks on the way up. Don’t rut up the roads and trails in your truck or ATV trying to get an extra 100 feet. Park before you get to the muddy sections and try to avoid them as much as possible. Just like your tracks in the snow, leave no trace. Have a great spring. We’ll be back next year with the first winter snows.
Avalanche conditions change for better or worse continually. Backcountry travelers should be prepared to assess current conditions for themselves, plan their routes of travel accordingly, and never travel alone. Backcountry travelers can reduce their exposure to avalanche hazards by utilizing timbered trails and ridge routes and by avoiding open and exposed terrain with slope angles of 30 degrees or more.
Backcountry travelers should carry the necessary avalanche rescue equipment such as a shovel, avalanche probe or probe ski poles, a rescue beacon and a well-equipped first aid kit.
Have a safe and pleasant spring!