Predicting Avalanches
Published 12:30 pm Friday, January 4, 2019
- Submitted photoThe Kip Rand weather station in the southern Wallowas honors the former director of the Wallowa Avalanche Center, who died in 2016.
A weather station high in the Wallowa Mountains that helps forecasters warn backcountry travelers about avalanche threats also honors a man who did the same work and who died in a snow slide in the Wallowas almost three years ago.
Kip Rand was director of the Wallowa Avalanche Center.
He died March 8, 2016, from injuries he sustained in an avalanche on Chief Joseph Mountain in the northern Wallowas, south of Joseph.
A seasonal weather station on the opposite side of the range, north of Halfway, is named for Kip Rand. The station, elevation 7,434 feet, is a key cog in the network of data collectors the Center’s forecasters use to compile avalanche forecasts available for no cost to skiers and others.
“The Kip Rand weather station is the only high-altitude weather station on the southern end of the Wallowa Mountains,” said Julian Pridmore-Brown, deputy director for the Wallowa Avalanche Center, based in Joseph.
Pridmore-Brown said Rand was the first to propose installing a weather station in the southern Wallowas.
It complements the Center’s other stations, at Salt Creek Summit east of the Wallowas, on Mount Howard near Wallowa Lake, and at Anthony Lakes in the Elkhorns.
The Avalanche Center issues forecasts for four zones — the Elkhorns, the northern Blue Mountains, and the northern and southern Wallowas.
The Wallowas have two forecasts because the avalanche danger can be substantially different across the range, Pridmore-Brown said. One of the bigger differences is that in most winters considerably more snow falls in the southern part of the Wallowas.
Two backcountry skiers were killed in an avalanche several miles from the weather station site in February 2014.
Snowfall amounts are only one of many factors, though, that influence the risk of avalanches.
Two others — wind and temperature — can have more noteworthy effects, and that’s why the Kip Rand and other weather stations are so vital in helping forecasters derive timely and accurate estimates of the relative risk, Pridmore-Brown said.
Wind, and especially wind that blows from a consistent direction at a speed of between 10 mph and 15 mph for an extended period, can cause slabs of snow to form on the leeward side of ridges, said Victor McNeil, the Avalanche Center’s executive director and one of its three forecasters.
If slabs accumulate atop layers of less dense snow, there is a greater risk of what are known as “wind slab avalanches,” McNeil said.
Because wind is such a crucial ingredient in avalanche danger, the Kip Rand and other stations were installed on ridges because winds tend to be stronger there than in sheltered valleys, he said.
The other main network of mountain weather stations in Northeastern Oregon — Snotels — are designed to measure the depth of snow and its water content, so they tend to occupy low-lying areas less prone to wind, which creates drifts that can artificially boost the snowpack.
Many Snotels lack anemometers, in any case.
Snotel data are useful because they give avalanche forecasters an idea of how much snow has fallen in a given period, McNeil said.
But adding the wind readings from ridgetop stations, such as Kip Rand, gives forecasters a much more refined picture of the avalanche danger, he said.
Temperatures are another important component because wide fluctuations, especially in a short period, can dramatically change the texture of the snow and potentially make avalanches more likely, McNeil said.
The ridge stations are helpful in this respect as well because temperatures, especially during inversions that are common in the region during winter, can be much warmer on the ridges than in nearby basins.
McNeil said avalanche forecasters don’t rely solely on weather data.
They also use shovels.
Forecasters, as well as volunteers, dig “test pits” so they can examine the layers within the snowpack, much as geologists study the rock strata in a highway roadcut.
The way various layers interact influences the avalanche danger — if heavy snow falls atop ice or a crusty layer formed by melting and freezing cycles, for instance, the threat can be high because the new snow doesn’t bond to the slippery layer.
The Kip Rand weather station was installed last winter but its data have been available to the public for just a couple weeks, after the station was added to the MesoWest network, which is linked to National Weather Service and other websites, Pridmore-Brown said.
(The network is at mesowest.utah.edu)
The station is just south of the Eagle Cap Wilderness boundary. It’s an area popular with both skiers and snowmobile riders, which is one reason Rand wanted to put a station there, Pridmore-Brown said.
“It’s a great location for what we wanted,” he said.
The station cost about $1,500. The Avalanche Center’s permit from the Forest Service requires that the station be in place only during the avalanche season — it will be removed in April.
Pridmore-Brown said the site has another advantage — reliable cell service.
That obviates the need to install solar panels and batteries to power the station, as is the case with the Center’s other stations, which beam their data via radio signals.
The Center’s annual $30,000 budget comes mainly from donations and its annual fundraiser, the Eastern Oregon Backcountry Festival at Eastern Oregon University. This year’s Festival is set for Jan. 25-27. Details are available on the Center’s website, www.wallowaavalanchecenter.org