|HighlightsSummer is quickly fading into winter across Colorado’s high country. Snowfall, strong winds, and cold temperatures have begun to build the foundation for the coming winter’s snowpack. It is time to put on your avalanche thinking caps if you are planning a trip into steeper terrain. Weather forecasts point toward a more winter like pattern as we start the month of October. Many locations have seen old snow persist on the ground this summer, meaning slab avalanches can develop in October with new and wind deposited snow on a hard smooth old snow surface. It is not unusual to hear of avalanche incidents in the fall. Please be thinking avalanche if you visit the high country.We will update the Statewide Avalanche Conditions as necessary. On November 1, 2014, we will resume our regular weather products, and our regular avalanche and snowpack forecasts around mid-November.
Avalanches are possible any time you find snow on steep slopes in Colorado. Nearly every fall, eager riders and
late-season hikers are caught off-guard when they trigger avalanches. Hunters traveling through the high country need to exercise caution on steep, snow covered terrain. Our next scheduled update is November 1, 2014. We will continue to issue updates via Twitter if we anticipate unusually dangerous conditions before then.
A couple of smaller storms moved through the state in September bringing some snow to the higher elevations. Most of this snow melted off, but some did linger on north aspects and on old summer snowfields. October started with a winter storm bringing our first real chance at lingering snow for the 2014-15 winter season. This new snow will form weak layers and with the addition of stronger winds, expect wind slabs. Think avalanche if you have plans to travel into the high country.
You can get current weather forecasts from the National Weather Service here.
Our Computer Model Forecasts are updated four times a day and will run through the summer. If you are going into the Colorado high country use our Weather Stations by Zone page to check current conditions.
Snowpack & Avalanche Discussion
Avalanches are possible in the mountainous areas of Colorado whenever you find snow on a steep slope. In general, you should consider the consequences of being caught in an avalanche before you cross any steep, snow-covered slope, but below are some avalanche problems you may encounter this fall. You can look here for observations of snow conditions and reports of avalanches any time of the year. We also want to hear your reports on backcountry conditions and avalanche observations, so please send us your observations.
Storm Slabs, Wind Slabs, and Loose-Dry Avalanches
Most avalanches happen during or right after a snow storm. But any time new snow falls and the wind moves it through the the terrain, avalanches are possible. New snow often has a hard time sticking to hard, icy old snow surfaces, so a fall snow storm can produce small avalanches if it falls onto old snow, grassy areas or rock slab. Even small avalanches are dangerous if they push you off a cliff, or into rocks, trees, or a gulley. The best way to manage these avalanches in the fall is to have a current weather forecast, recognize when there is enough new snow to produce storm avalanches, and select terrain that minimizes your exposure to the risk (avoid areas where there was old snow, wind pillows along ridgelines, cross-loaded features like rock outcrops and subridges). Here is an example where a new-snow avalanche produced an fatal accident a few years ago.
Wet Slab and Loose-Wet Avalanches
As the snow heats up and begins to melt, water moving through the snowpack can produce avalanches. The most common wet avalanches are loose, sluff or point-release avalanches. These are most dangerous if they can push you off a cliff, or into rocks, trees, or a gulley. You can manage these by starting your tour early, when the snow is frozen, and ending your tour early before the snow gets too wet. Watch the overnight low temperatures at high-elevation weather stations, but remember that air temperature, cloud cover, and wind all affect how the snow freezes each night. Wet slab avalanches are much more dangerous. These often occur when melt water hits a persistent weaker layer that formed earlier in the winter or during a dramatic warm up that lasts a few days. The snow conditions that produce wet slab avalanches last longest on high-elevation, northerly slopes as we move into summer. Look at the old snow layers to see if they are still dry or turning to coarse spring-time snow. Regardless of what wet avalanche you are worried about, remember to stay off and out from under steep snow-covered slopes when you start to sink into the wet snow more than about 6 inches. Here is an example of a fatal accident in a wet slab avalanche from two years ago.
Throughout the winter, strong winds build large over-hanging snow features along ridgelines. These cornices can break off at any time of year, but also break and roll onto lower slopes during spring melt. It is hard to predict when these large masses of snow will break, so it is best to avoid traveling under them and give them a wide berth when you are traveling along them. If your route goes under one, use a similar approach as wet slab avalanches and look for a good overnight freeze and try to get past them early in the day. Remember that the sun may hit them earlier than it hits the slopes below them.