A lahar, or volcanic mudslide, coming off Mount Baker could rush down valleys and stream through channels at an average of 20 to 40 mph, with enough force to move houses, trees and boulders close to the source of the flow.
It is the primary danger posed by Mount Baker, an active and glaciated volcano that looms over Whatcom County.
Seeking to protect the public from such hazards, the county is moving toward putting up signs to let people know they’re in a lahar area and creating evacuation routes for when such flows of mud, debris and water roll down from the 10,778-foot Baker.
That’s what the County Council is considering as part of an early warning system, which doesn’t exist in Whatcom County, after residents of the Mount Baker foothills urged them to take those steps instead of approving land use rules they feared were restrictive and would harm their businesses and the economy of their small communities.
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The issue surfaced Oct. 25 during a public hearing about proposed changes to the county’s critical areas ordinance, which was last updated in 2005.
The ordinance aims to protect habitat, including wetlands and aquifers, and reduce risks to people in geologic or other hazardous areas in unincorporated Whatcom County, which is the council’s responsibility, using the latest available science and information.
The hearing was simply meant to be an initial overview as the council won’t return to the ordinance until January, when it will consider it more exhaustively. The council instead got an earful from concerned businesses and residents in the foothills, which include the communities of Glacier, Deming and Maple Falls.
It’s a great place to live. We choose to live there. We understand the dangers of the volcano.
Shelly Crabtree, general manager for Black Mountain Ranch, a private campground near Kendall
They worried the proposed change to the critical areas ordinance as it pertained to lahars would be damaging, specifically the portions that allowed a maximum of 25 to 100 people in a building – gradations that were based on how much time people had to escape a volcanic mudflow.
“These regulations represent a vast overreach which will unnecessarily restrict private property rights in order to protect against a hazard which may not occur for thousands upon thousands of years, if at all,” attorney Seth Woolson wrote to the council on behalf of client Mt. Baker Bibleway Camp, located between Maple Falls and Glacier.
“Simply stated, the speculative risk does not warrant the degree of regulation proposed,” he continued, adding that the volcano would provide days or weeks of warning of unrest, enough time for an evacuation.
For their part, county planners said the proposed changes actually were less restrictive when it came to land use.
Others told the council that people who play and live in the shadow of Mount Baker understand the risks. And why would the county enact rules that would restrict people from living and having businesses there, they wanted to know, if such limitations don’t exist because of tsunami danger, which threatens coastal communities such as Birch Bay?
“It’s a great place to live. We choose to live there. We understand the dangers of the volcano. Everybody is aware of it, and we go there anyway,” said Shelly Crabtree, general manager for Black Mountain Ranch, a private campground near Kendall that can have as many as 4,000 people on a given weekend.
County Councilwoman Barbara Brenner agreed, asking the planning department to remove the proposed changes from the critical areas ordinance.
“We can’t regulate to protect everybody from everything,” she said, adding that the county should plan for lahars like tsunamis, with evacuation routes and education of the public.
Volcanic activity in the Mount Baker area dates back more than 1 million years, with the largest eruption of today’s Baker occurring 6,600 years ago. That sent what the U.S. Geological Survey has described as a “blanket of ash” more than 20 miles to the northeast.
In 1843, the volcano exploded and formed Sherman Crater. Explorers at the time described rock fragments coming down “like a snowfall” and the forest on “fire for miles around.” That was when the mountain last erupted.
A lahar occurred in 1845 on Boulder Creek, and another in 1891 when a side of Mount Baker collapsed and created a lahar that traveled more than six miles and covered one square mile.
In 1975, plumes of steam from Sherman Crater raised fears that increasing heat would melt nearby glaciers and cause lahars.
Worried that lahars would flow into Baker Lake or Lake Shannon to the east, damaging the Upper Baker Dam and causing flooding, officials evacuated area residents and businesses, and closed campgrounds around Baker Lake in June 1975.
Then Baker calmed, but that doesn’t mean it’s dead.
“Geologists consider Mount Baker to be active, as it has the potential to erupt within the near future. There is obvious heat within the volcano, evidenced by the continual steam plumes of boiling water. Also, there are the sulfurous gases, which are coming off a magma body at an unknown depth,” explained Dave Tucker, a Bellingham geologist who is an expert on the volcanic history of the mountain and is the director of the Mount Baker Volcano Research Center.
When it comes to Baker, geologists see lahars as the greatest concern. They could come with advance warnings from volcanic activity, or they could occur unexpectedly because of a collapse that causes a slide.
When might the volcano erupt again?
“Not possible to say. Within weeks, or within thousands of years,” Tucker said. “We might have around three weeks of warning of a possible eruption, as rising magma would generate shallow and frequent earthquakes.”
But, Tucker warned, “Baker is badly under-monitored.”
“USGS standard calls for five seismometers to track possible magma movement,” he said. “There are only two.”
And if you’re in the area and there’s a lahar, don’t try to escape by going down.
“Get away by running uphill. You can’t outrun a lahar if you stay in the path,” Tucker said. “You likely won’t be able to drive away from one, either.”