Guest post by David Middleton

Rural Alaska

‘The permafrost is dying’: Bethel sees increased shifting of roads and buildings

Author: Lisa Demer

Updated: 1 day ago calendar Published 2 days ago

Chief Eddie Hoffman Highway, seen on June 28, is the main thoroughfare in Bethel, and one of few paved roads. It has become a roller coaster of a ride over the past couple of years. The state Department of Transportation is studying whether heaving from the thaw-freeze of permafrost is a factor. (Lisa Demer / Alaska Dispatch News)

BETHEL — Along the main thoroughfare here, drivers brake for warped asphalt. Houses sink unevenly into the ground. Walls crack and doors stick. Utility poles tilt, sometimes at alarming angles.

Permafrost in and around Bethel is deteriorating and shrinking, even more quickly than most places in Alaska.

Since the first buildings out here, people have struggled with the freeze and thaw of the soils above the permafrost. Now those challenges are amplified.

“What they are saying is the permafrost is dying,” said Eric Whitney, a home inspector and energy auditor in Bethel who has noticed newly eroding river banks, slanting spruce trees and homes shifting anew just weeks after being made level. “I’m just assuming it is not coming back while we’re around here.”

[…]

Above the permafrost in Southwest Alaska, an active layer of soil, often peat, freezes and thaws each year. With air temperatures warming too, the active layer is growing bigger, consuming what had been thought of as permanently frozen.

Thirty years ago, crews would hit permafrost within 4 to 6 feet of the surface, Salzburn said. Now they typically find it 8 to 12 feet down. To install piling deep enough into permafrost to support a house, they used to drill down about 18 feet.

“Now we are going to depths of 35 feet,” Salzbrun said.

“There is a definite change,” said another Bethel contractor, Rick Hanson of T and H Leveling.

[…]

Alaska Dispatch News

“The permafrost is dying!”

“Thirty years ago, crews would hit permafrost within 4 to 6 feet of the surface, Salzburn said. Now they typically find it 8 to 12 feet down.”

Funny… Apart from this past year, Bethel AK is no warmer than it was in the 1930’s.  However, thirty years ago, Bethel was definitely colder than it is now or was in the 1930’s…

Figure 1. Bethel AK Annual Mean Temperature, GHCN v3 (adj) + SCAR data. (NASA GISS)

There is no statistically meaningful trend in the annual, summer or winter temperatures at the Bethel AK station:

Figure 2. Bethel AK. Annual (metANN), Summer (J-J-A) and Winter (D-J-F) temperatures. (NASA GISS)

Bethel’s permafrost may be problematic due to the fact that the average annual temperature is just below freezing and gets well above 0°C in summer and it may thaw to a deeper depth than it did 30 years ago… However, there’s no evidence that the permafrost is dying any more than it would have been dying in the 1930’s.

Featured Image: USGS