University of Alaska Fairbanks logo bear University of Alaska Fairbanks

Frozen Debris Lobes

Looming over Alaska's most economically important highway

What are Frozen Debris Lobes?

Frozen debris lobes (or FDLs) are slow-moving landslides occurring in permafrost. Made up of soil, rocks, trees, and ice, many are located on the slopes in the southern Brooks Range of Alaska.

Why do we care about FDLs?

FDL-A is approaching infrastructure at an increasing rate.
In 2022, it collided with the old Dalton Highway alignment.

  • Distance to New Dalton Highway as of July 26, 2023: 107.8 m
  • Current average annual rate: 2.1 cm/day

Today's FDL-A Location

Current image of FDL-A

Timelapse of FDL-A for January 2021 to September 2023

North Time-Lapse of FDL-A for August 2020 to July 2023

Impact Schematic

Frozen Debris Lobe impact schematic

Cross section of a Frozen Debris Lobe

Drawing: cross-section of a frozen debvris lobe

Illustration by Dan Darrow © 2014.


Source: Frontier Scientists
Source: UAF Cornerstone
“Attack of the Debris Lobes”
Cartoon depicting screaming figures in foreground as frozen debris lobes approach from background
Source: KUAC radio broadcast
“Debris Lobe Threatens Dalton Highway”

View all »

FDL-inspired video productions

The inspiration for "Not a Rock Glacier" is B-52's Rock Lobster (Instrumental) available on iTunes.

The inspiration for the FDL rap above is Uptown Funk by Mark Ronson (Karaoke Instrumental).

The inspiration for the FDL rap above is "Ice Ice Baby" by Vanilla Ice available on iTunes.

The inspiration for the FDL rap above is "Whole Foods Parking Lot" by DJDave.