By Jeff Thompson
Jeff Thompson from the Idaho Panhandle National Forest Avalanche Center here. This is our last update of the season. Spring is generally a safer time to travel in the mountains, but there are some rules to live by. The following are some helpful hints to guide you in your spring trips to the mountains.
•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 boot-tops or you’re laying on the throttle to move, it’s 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. When we do get new snow watch for the type of surface it is bonding to. New snow on an ice crust that is experiencing melting during the day can be extremely unstable, especially if it is wind-loaded.
•Finally, 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.
•On your ventures into the high country remember to respect old terra firma, the brown stuff, that sticks to your boots. 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.
•Backcountry users 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, a rescue beacon and a well-equipped first aid kit.
•The high country in the Panhandle is sitting at 98 percent of average for snowfall. The pack may stick around for a while this season. 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. We’ll be back next year with the first sign of snows. Have a good spring!