Chilkat Valley News - Serving Haines and Klukwan, Alaska since 1966

Avalanche Center tracks rainfall data

 

January 21, 2021



A new rain-monitoring tracker on the Haines Avalanche Center’s website was created earlier this month and is intended to provide a convenient location for residents to assess rainfall data and forecasts as some worry about the effects of rain and warmer temperatures on landslide potential.

“A lot of us are lying in bed at night listening to the rain hit the roof and it sounds like it’s raining really hard and it’s kind of freaky,” avalanche center director Erik Stevens said. “But when you look at the actual data of how much it did rain, often- times we find out it didn’t rain as much as we thought. If it does rain a lot then people will know, ‘This time it’s different. It did rain more than in these past storms so maybe I keep my mind open a little bit to be on alert.’”

Viewers can see how much rain has fallen in the previous six hours, 24 hours, 48 hours and seven days compared to the December weather record event. Below the data is a graph showing rainfall data along with a National Weather Service precipitation forecast for a similar time range.

Stevens said the data is coming from the rain gauge at the airport, an area that consistently sees less rainfall than town because it’s in a drier microclimate. It’s the only heated gauge in town that records melted snowfall.

“I’d like to see a reliable, heated precipitation gauge in town. We do see more rain in town than at the airport. It’s a significant difference. The airport is in a very dry microclimate. For example, this last weekend, the airport reported .67 inches in 24 hours and during that same period (near Letnikof) there was 1.2 inches, almost twice as much.”

As of Tuesday afternoon, just more than two inches of rain fell at the Haines Airport in 48 hours. Late Monday night, the rain triggered an avalanche at 21 Mile (mistakenly identified as a landslide at 19 Mile by Nixle, an emergency alert text message service.)

A small landslide slid on a lower portion of the Dec. 2 Beach Road slide path during rainfall between Monday and Tuesday.

Haines Department of Transportation foreman Matt Boron said he cleared rock and other materials from three areas along Lutak Road. “There were some rocks on the road and some debris here and there out Lutak, but I wouldn’t call it a slide. I would say it was normal movement for Lutak,” Boron said. “We had an avalanche at 21 Mile. It was snow, not mud and rocks. That is an avalanche chute that we know of but it has not come across the road for many years.”

Stevens said as state geoscientists collect more data across the Chilkat Valley, he hopes more weather gauges will be installed to refine data and perhaps establish thresholds for landslide triggers.

“Let’s say there’s one night a year where it’s raining hard enough where we’re meeting some sort of critical threshold value. It would be good for people to know when that day is. Maybe this is the one night of the year I shouldn’t stay in my house. I don’t know if we’re going to get to the point where we can define that or not. My hope is that with enough research that might be possible.”

The Sitka Sound Science Center, with state, federal and nonprofit partners, has been working on just such a goal since slides killed three near the town in 2015. With a grant from the RAND Corporation, the science center has installed rain gauges, water pressure gauges and other monitoring systems with the aim of putting the data on a user-friendly website where people can make their own risk assessments.

Stevens said since December, he regularly receives calls about how the weather could affect local landslides. “Pretty much all the time,” Stevens said of how often he gets such calls. “It has gotten better since we started this page with people asking if it’s safe or not. I can never really answer that question. It is helping people to make decisions on their own.”

The data can be seen at Alaskasnow.org/haines/rain.html. He said the page has received about 200 views a day since it went up two weeks ago.

 
 

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