A weather station mounted on Mount Ripinsky last month is the second planted on local peaks in the past two months.
A sophisticated, $175,000 station went up near 20.5 Mile Haines Highway in August, a high-elevation station aimed at monitoring rainfall and soil temperatures. It’s the first of its kind in Southeast Alaska.
Information it provides – including barometric pressure, wind speed, air temperature and relative humidity – went online last month and already is being used by local pilots, said Dr. Gabriel Wolken, program manager for the state’s Climate and Cryosphere Hazards Program.
“Pilots have called me and said they appreciated the information. People are already using it,” Wolken said.
Sited at 4,636 feet on Takshanuk Ridge, the station is intended to be the first step toward an “early warning system” for landslides that occur regularly at 19 Mile and 23 Mile Haines Highway. It also will provide data that will help weather forecasters and others who study climate statewide.
The station is funded by the state Department of Transportation, the state Division of Geological and Geophysical Surveys and the Cold Regions Research and Engineering Laboratory, an agency of the U.S. Army Corps of Engineers. Wolken’s program is part of DGGS.
The station is strategically located between the two landslide locations that require such continual maintenance that local DOT crews sometimes leave heavy equipment at the site. Removal of debris there costs up to $200,000 per year, DOT has previously said.
Wolken said as much as three times as much rain falls on tops of mountains as falls in town. Knowing rain volumes near the tops of the mountains will help the National Weather Service with its weather and flood forecasting. It might eventually help local DOT road crews know when to stand by, head up the highway, or issue landslide warnings for motorists, Wolken said.
Mitch McDonald, regional engineering geologist for DOT’s Southcoast Division, characterized the weather station as helping provide an understanding of the micro-climate uphill of the highway, where up to 20,000 cubic yards of earth can move without hitting the road.
While it’s much too early to talk about “predicting” slides, the state needs to learn more about the site, particularly what’s happening off the right-of-way. “There’s no hard data. We’re trying to get a handle on the mechanisms. There’s never been a detailed study at that site. We’re trying to get a handle on it using the technology,” McDonald said.
A fatal landslide in Sitka last year drove home the importance of understanding mountain-top micro-climates, McDonald said. “Alaska has a big void of data compared to down south. This is a big step toward being proactive. That’s what we’re trying to change our methods to.”
The station includes four soil temperature sensors at different locations and depths, allowing scientists to begin collecting information on permafrost on the ridge, including location and vulnerability. Alpine permafrost stabilizes fractured rock and unstable sediments, Wolken said. “As permafrost starts to thaw in those areas, we’d expect it to become more unstable. As that happens, we’d anticipate more debris flows.”
The station is important for weather forecasting and modeling because topography – low valleys and steep mountains – have a big influence on local weather. However, most weather stations in Alaska are located at sea level.
In Haines in particular, the weather is influenced by mountains, Wolken said. “Unless we know what the weather is at high elevation – the wind, temperatures and precipitation – we’re essentially trying to guess what’s happening.”
The station is independent of and unrelated to one placed at 2,600-feet elevation on Mount Ripinsky two weeks ago by the Haines Avalanche Information Center. As an intermediate elevation data point, the Ripinsky station will be “very helpful” to his studies, Wolken said. Local avalanche center director Erik Stevens has said he can use information from the high-elevation station for avalanche forecasting as well.
“It’s all really great for people in Haines and for the work we do monitoring and understanding weather patterns,” Wolken said.
There are two high-elevation weather stations operating near Cordova and Valdez and three others around the state will come online soon, Wolken said. Maintenance on the new Haines station should be inexpensive and may include occasional battery changes and replacement of sensors sometimes broken off by rime ice.
In other areas, communities have partnered to provide maintenance. “I suspect the community will start to appreciate having it and people will want to keep it going over the years,” Wolken said.
The station does not include a snow height sensor, partly because snow depths can vary widely in a relatively small area on a mountain, but agencies might consider that in the future, Wolken said.
Data from the station is at http://dggs.alaska.gov/climatehazards/weatherstations/#4.
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