The record-breaking snowfall last winter created residual hazards for Sierra hikers well into the summer months. And the conditions are still taking a toll on backcountry travelers.
According to state Department of Fish and Wildlife officials, 122 mule deer have been confirmed dead near two mountain passes due to icy conditions that have remained on the steep slopes since last winter’s snowfall. The deer lost their footing while attempting to navigate the ice on near vertical inclines, which are along their historic migration routes. The snowbanks repeatedly thawed and froze throughout the summer, creating the hazards.
The deer were unable to retain their footing and plunged down the icy slopes. They either died immediately or were seriously wounded when they landed in the boulder field below.
There is a traditional fall deer migration over both Bishop and Shepherd passes, which are located on the Sierra Crest about 35 linear miles apart. Bishop Pass, at an elevation of 11,972 feet, is located on the boundary of Kings Canyon National Park and the John Muir Wilderness in
Inyo National Forest (west of Big Pine); to the south is Shepherd Pass, elevation 12,050, straddling Sequoia National Park and the Inyo’s John Muir Wilderness (west of Independence). The fatalities occurred on the Inyo side of the crest.
“The deer died while attempting to travel down snowfields that persisted from last winter,” reported Tom Stephenson, a senior environmental scientist for the California Department of Fish and Wildlife.
Recent freezing temperatures turned soft snow to slick ice, according to Stephenson.
Stephenson, who investigated the mortalities at Bishop Pass, said most of the deer appeared to die either immediately or after traveling a short distance from the base of the snow. The ice wasn’t selective; included in the casualties are bucks, does, and fawns. Many of the deer didn’t die upon impact, but instead suffered broken legs and other critical injuries.
Now that new snow fell this week in the higher elevations, the dangerous conditions for wildlife should be reduced, according to the CDFW.
“New snow of sufficient depth prevents the deer from sliding down the icy snowfield,” Stephenson explained.
Mortalities were first reported on October 30 to the Bishop office of CDFW by a distraught hiker who made the gruesome discovery while crossing Bishop Pass. The next day, a mountaineer in the Shepherd Pass area also reported seeing a great number of deer that had apparently died near the pass and then, a few days later, the climber reported additional mortalities.
As of November 20, CDFW has confirmed that 78 deer perished in the vicinity of Bishop Pass and 44 deer died near Shepherd Pass.
“This is a horrible thing to witness, but hard things happen in the natural world,” said Deb Schweizer, public affairs officer for Inyo National Forest (Deb was formerly the fire information officer at Sequoia-Kings Canyon National Parks).
Similar incidents are reported to have occurred in 1954 and 1995 in the same approximate Bishop Pass location. In 1954, Fred Jones, a wildlife biologist doing field research in the Eastern Sierra, reported approximately 26 deer slid on the ice and fell to their deaths on rocky terrain on the east side of Bishop Pass.
Forty-one years later, in 1995, a similar accident in the Bishop Pass location was described by CDFW biologists Vernon Bleich and Becky Pierce. Again, the deer were following traditional migration routes of the Round Valley and Goodale herds, descending from the higher elevation summer range on the west side to the Sierra Crest’s east-side valleys where they spend the winter.
Upon this discovery and because of strong public interest and the potential for additional losses, Bleich and Pierce proposed using hand tools to enhance the trail across the ice and covering the trail with sand to increase traction for other deer migrating to Round Valley. But permission to implement this strategy was denied by wilderness staff from Inyo National Forest because it would conflict with “natural processes” in wilderness.
The Round Valley herd, named for where the deer spend the winter, has a population of about 3,000 animals. The Goodale herd, which winters between Big Pine and Lone Pine, is estimated to consist of 5,500 animals.
Deer and other wildlife have been struggling with five years of drought, then an abundant snowpack last winter, all of which contributed to a die-off of some species, including deer and bear.
The Bishop resource management plan provides protections for the migratory routes and winter ranges of the Round Valley and Goodale herds.