December 17, 2024 Tsunami: Whitehorse, Yukon, Canada

Ref #13888:

Derek Cronmiller, the head of surficial geology with Yukon Geological Survey, says the landslide moved about 20,000 cubic metres of soil, snow and trees, directly into the river. He says that's larger than all of the landslides seen on the Whitehorse escarpment along Robert Service Way in recent years.

For Cronmiller, the most unique element of the landslide was that it caused what he referred to as a "tsunami." "It broke through the ice of the Takhini River and created a large displacement wave , and it broke a lot of the ice and it rafted large chunks of river ice up to 250 meters away ... which can be very destructive, damaged trees and things like that," Cronmiller said. The landslide was in a relatively remote area and didn't cause any threat to public safety, he added. However, the debris has blocked "a little bit more than half" the channel, he said. He says the area affected by the landslide-generated wave is much larger.

Cronmiller also refrained from linking the landslide to climate change.

Ref #13889:

A rather unusually timed landslide on the Takhini River bank on the edge of Whitehorse this winter generated a “small” tsunami that reminded a Yukon geologist of Dawson City's risk.

Cronmiller noted the recent Takhini River slide took place in a relatively remote part of the river just south of the Eclipse Nordic Hot Springs. No one was hurt and no infrastructure was damaged or put at risk due to the local slide, per Cronmiller.

The earliest photo known to the News of the recent Takhini River landslide comes from Dec. 23, 2024, which Cronmiller said indicates the slide occurred earlier that day or within a few days of that photo being taken. Cronmiller’s team was notified about the slide by Liam Ferguson, who Cronmiller described as a local collaborator involved with Northern Sonic Drilling and Consulting Inc.

Ref #13898:

On 17 December 2024, the 118,000 cubic metre silt and clay Takhini River landslide occurred on a cut bank of the Takhini River, 25 km northwest of Whitehorse, Yukon, Canada. The landslide, located at [60.8611, -135.4180], broke through the river ice and generated a tsunami. The tsunami transported blocks of river ice up to 250 m from the slide deposit and destroying vegetation on the opposite riverbank splintering and uprooting trees in excess of 20 cm diameter.

Four surviving trees record tsunami damage up to 2.5 m in height. The tsunami had identifiable impacts affecting 72 000 m2, approximately 2.6 times the 28,000 m2 footprint of the landslide.

Though landslides on the banks of the Takhini River are not unusual, the midwinter timing of this slide and the resultant damage from ice blocks rafted by the landslide-generated tsunami make this a novel landslide with important hazard implications. The Whitehorse area has seen many landslides on glaciolacustine escarpments in recent years. Landslides on the Whitehorse escarpment have caused major disruptions in the city each spring since 2022. These slides have been attributed to snowmelt and increased groundwater levels from above average snowpacks from 2021-2023.

Ref #14194:

On 17 December 2024, a 118,000-m3 landslide on a cut bank of the Takhini River, Yukon, broke through the river-ice and generated a tsunami. The tsunami transported blocks of river-ice up to 250 m from the landslide deposit and destroyed vegetation on the opposite riverbank […] Snapped branches and impact scars on the trunks of four surviving trees in the tsunami impact area record damage from rafted ice up to 2.5-m height.