High precipitation totals and high temperatures are combining to cause continued high avalanche dangers in the Juneau area through at least 7 a.m. today, according to a notice on the City and Borough of Juneau’s website.
According to the website, natural avalanches were seen in the White and Berhands paths areas, along Thane Road, in Chop Gulley above the Flume Trail, Eaglecrest, Showboat Ridge and mountains Troy and Ben Steward.
“Most of (yesterday’s) avalanches appeared to be running on the innerface between two storm cycles,” according to the post on the city’s website, which is credited to Tom Mattice, the city’s avalanche expert. “Temperatures dropped (the) night before last and we placed dry snow on top of the (rain-wetted) surface in place. The loading rates were VERY high. As we continued to load the dry snow on a greasy weak layer, temperatures were warming. So we placed a block of snow on top of a weak layer of (champagne) glasses that were resting on a greasy
(S)lurpee. As this rapid loading continued it was only a matter of time before we started to see slope failure.”
Mattice is projecting the avalanche danger to subside in the coming days. In an interview with the Empire, he said while the forecast calls for continued precipitation in the coming days, the amounts will be significantly less than the city has seen in the last few days. He said the levels will be four-tenths of an inch per day or less today and Tuesday.
However, an inch of rain or more per day can increase the danger, which he said is forecast in a 24-hour period from Tuesday afternoon to Wednesday afternoon.
Additionally, while the temperatures in the city will remain fairly constant and above freezing for the week, the freezing line is moving lower in elevation, which will help the snowpack solidify.
While the danger will be reduced, it still exists, especially from human activity such as skiing or snowmobiling.
“The danger won’t go away completely until the temps cool off,” he said.
Mattice’s post on the city’s website encourages people to avoid Flume and Perseverance trails, stay away from urban avalanche zones between the Behrends and White subdivisions, and to limit travel along Thane Road and in the backcountry. If you must be in those areas, be sure to notify someone and take along an avalanche transceiver, probe, partner and a shovel.