As Glaciers Melt, Mt. Shasta Could See More Mudslides

Mt. Shasta, at 14,179 feet, the second highest peak in the Cascades mountains and the fifth highest in California. (©Joe)
Mt. Shasta, at 14,179 feet, the second highest peak in the Cascades mountains and the fifth highest in California. (©Joe)

A giant mudslide sent mud and debris hurtling down the southeastern flank of California’s Mt. Shasta in late September. Experts believe glacial melting, hastened by a three-year California drought, loosened giant ice blocks at the small Konwakiton Glacier midway up the peak, dislodging earth and rocks dammed up under the ice.

U.S. Forest Service climbing ranger Jonathan Dove of the Shasta-Trinity National Forest was on a ridge above the mudslide when it happened. “It sounded like a freight train barreling down the canyon,” he told the Los Angeles Times.

Mt. Shasta’s September mudslide was the worst the area had seen in 20 years, according to U.S. Forest Service Hydrologist Steve Bachmann, who spoke with Redding.com. Bachman warned that another chunk of glacier could easily dislocate, shunting a new torrent of mud and boulders down the mountain.

Scientists attribute the accelerated melting on the Mt. Shasta glacier, in part, to a lack of insulating snow pack. And that’s bad news. Due to climate change, snowpack is expected to decline 25 percent to 40 percent statewide by 2050. Mt. Shasta, which is a dormant volcano in the Cascades mountain range, has the most glaciers of any mountain in California.

No one was hurt, and no homes were damaged from flooding, but the mudslide buried two roads in the tiny town of McCloud, in northern California’s Siskiyou County, under mud, large boulders and fallen trees. Authorities were forced to close the roads to traffic, and one of them will not likely be reopened until next year. The mudflows, which came down the appropriately named Mud Creek, also cascaded into McCloud River, popular with fishermen, and fed into Shasta Lake, which is only a quarter full due to drought.

McCloud River in summer. (©Carlos Wolters)
McCloud River in summer. (©Carlos Wolters)

Forest Service officials told the Sacramento Bee that the drought, combined with hot summer temperatures, may have created a small lake atop or within the glacier, causing a chunk of it to collapse, which then released the dammed up water in a small outburst flood. These glacial outburst floods have a name in Iceland: “jökulhlaup.” (Read more about them on glacierhub, here.)

Mt. Shasta’s Mud Creek has seen its share of mudslides in the past 100 years. The biggest occurred in 1924, when mud and debris spread over an area 8 miles by a half a mile, blocking the railroad tracks and severing water lines to the town of McCloud for two days. The mudslide made the front page of the local Redding Courier-Free Press six times in the weeks following the incident.

McCloud railroad. (©Drew Jacksich)
McCloud railroad. (©Drew Jacksich)