Warmer Temps + Melting Snow = Park-wide Challenges. Sylvan Pass Slides Delay East Entrance Reopening.

Yellowstone National Park road crews and avalanche experts are working to clear Sylvan Pass of more than 20 feet of snow and assess the continuing danger of wet snow slides that have kept the road closed since May 11. Four significant slides in the pass – one resulting in a debris field 70

yards wide and 20-30 feet deep across the road – have occurred in the past
36 hours.   Consecutive days of mild spring temperatures continue to
deteriorate high-elevation snowpack conditions and are expected to delay
the reopening of Sylvan Pass for an indeterminate time until the safety of
motorists can be assured.

The park is currently redirecting heavy road clearing equipment to support
reopening operations, and avalanche crews searched the slide area today
with probes and canine rescue teams to ensure no motorists were caught in
the slide.  An unoccupied government vehicle sustained damage when it was
partially buried in a major slide as a ranger was conducting an assessment
of the area on foot May 11.  The ranger was uninjured in the incident.
Explosives were used today by park officials to try and bring down some of
the heavy, wet snow.  Thirteen of 18 of the detonations were successful in
releasing large amounts of snow.

This snow slide activity is expected to continue until the weather pattern
returns to freezing night time temperatures.  The current forecast for the
Sylvan Pass area is for daytime temperatures in the 50s over the next two
to three days, which will continue to warm the heavy snowpack and make it
increasingly unstable.  Overnight lows in the past 48 hours have dipped
just enough below freezing to create a thin layer of ice, but that crust
melts quickly by midday.

A blanket of heavy melting snow in the park’s interior has also contributed
to the roof collapse of the RV repair facility at Fishing Bridge and caused
roof damage to roof of the Grant Village Visitor Education Center.  No
injuries were reported in either incident, and repair work is underway.

Yellowstone’s North and West Entrances opened April 15, the East Entrance
opened prior to the slide closure on May 6, and the South Entrance opens
tomorrow at 8:00 a.m.  Some areas of the park such as Mammoth Hot Springs
have already been experiencing the arrival of green grass and warm spring
sun.  Other areas remain wrapped in deep snow and chillier temperatures.
Snow and ice still present in road turnouts and on thermal area boardwalks
will make walking difficult or impossible for several more weeks.

May in Yellowstone means it is not uncommon for visitors to have both
winter coats and shorts packed in the
same travel bag.