Backcountry Travelers in Grand Teton National Park Advised Of Avalanche Danger

An unusually heavy snowpack, and a long, cold, and wet spring, have left relatively high avalanche conditions in Grand Teton National in place longer than usual. NPS photo this past winter.

While the bountiful winter is recharging both reservoirs and lakes in the Rockies and High Sierra, it also has lengthened the avalanche season for potential slides. In Grand Teton National Park the especially huge snowpack has officials warning backcountry travelers to be cognizant of avalanche conditions.

Grand Teton officials call their existing snowpack "unprecedented" for this time of year. "Unusual conditions exist due to an unseasonably cool and wet spring following a record winter snowfall with 732 inches recorded at the Raymer plot on Rendezvous Mountain (elevation 9,300 feet)," a park release stated.

"The normal transition from winter to spring to summer is substantially delayed, and the snowpack has not yet consolidated. Avalanche danger is expected to remain elevated during this slow transition period. As a consequence, Grand Teton National Park rangers advise extreme caution for any backcountry travel (hiking, skiing or climbing), as well as for backcountry camping."

Often by this time of year the park's snowpack has waned quite a bit. But this year things are different. "Several cornices and deep snow pockets remain throughout the mountains," says park spokeswoman Jackie Skaggs. "These areas may be prone to releases over the next several weeks, potentially producing large avalanches.

"The avalanche danger increases rapidly during periods of intense sun, a quick rise in temperature, or during and just after a period of high precipitation," she adds. "These are the very conditions that may occur as more seasonable weather finally arrives in Jackson Hole."

In light of the potential for slides, the park has issued the following guidelines for backcountry hikers and skiers:

* Be prepared for more winter-like conditions than are typical for June.

* Carry appropriate avalanche equipment and basic emergency items.

* Get an exceedingly early start on a backcountry trip, and don’t travel alone.

* Avoid being on or underneath steep, snow-covered slopes during the heat of the day.

* Be particularly alert to changing conditions and surroundings (i.e. cornices on cliff areas above a trail or travel route).

* Select a backcountry campsite well away from avalanche run out zones.

* Consider route finding abilities and snow assessment skills before heading onto Teton trails.

* Contact the Jenny Lake Ranger Station at 307.739.3343 or review current trail conditions at www.tetonclimbing.blogspot.com before heading into the backcountry.

The winter's final avalanche hazard report provided on June 12 by the Bridger-Teton National Forest Avalanche Center stated, “… At the upper elevations, the new dense snow has accumulated on warm wet old snow surfaces. At the mid-elevations the snowpack is rain soaked and unstable. Wet loose and wet slab avalanches are possible on very steep slopes at mid and upper elevations. These wet snow avalanches could release naturally, be triggered by a cornice failure, or by humans. Once triggered these wet slides could entrain large volumes of snow and become destructive.”