The runoff appears to be well under way in the South Fork Flathead drainage, with Spotted Bear District Ranger Deb Mucklow reporting a sharp increase on the South Fork River to flows that she has never seen before.

“I’ve only been here since 1999, but it’s the highest I’ve personally observed,” Mucklow said from the Spotted Bear Ranger Station Tuesday afternoon.

On Monday night, the river was roaring.

“It was very noisy,” Mucklow said. “We’ve had very large trees with their roots attached and other debris just banging against the rocks.”

There was a sustained downpour of rain overnight, and Mucklow speculates that played a big part in the river rising more than 2 feet since Monday evening.

The U.S. Geological Survey has a river gauge at Twin Creek about eight miles north of the ranger station that shows the river rising from 12 to 14 feet on the gauge with flows now at 26,400 cubic feet per second.

“It’s a pretty phenomenal event to be witnessing,” Mucklow said.

While the river is still within its banks, the Forest Service is urging the public to use caution around the South Fork and other rivers and streams.

Tributaries feeding the South Fork upriver from the ranger station, such as Mid Creek and Bear Creek, no longer can be safely forded on foot, she said, and crossing the swollen creeks would even be dangerous to cross with stock.

The level of Hungry Horse Reservoir has risen about eight feet during the last week, and about 30 feet since mid-May with increasing inflows. In early May the reservoir had been dropped to its lowest elevation in years to provide storage space.

Hungry Horse Dam Administrator Dennis Philmon said the reservoir is currently at an elevation of 3,506 feet, about 50 feet short of its full-pool elevation. Outflows from the dam were dropped from 8,000 cfs to 3,240 cfs on Tuesday because of rising flows on the main Flathead River downstream from the dam.

The National Weather Service still is forecasting the Flathead River at Columbia Falls to reach flood-stage flows of 50,100 cfs today and Thursday.

The Middle Fork of the Flathead is expected to reach several inches above flood stage today.

Flathead Lake, meanwhile, is still two feet below its full-pool elevation of 2,893 feet, and outflows from Kerr Dam have recently been running at 43,100 cfs.

In other runoff-related news, the Whitefish Pilot is reporting that saturated soils triggered a massive landslide on Lookout Ridge near Big Mountain.

According to Whitefish City Manager Chuck Stearns, the crown of the slide was about 60 feet wide and 10 feet deep, and the slide ran about 300 vertical feet along a swath about 1,000 feet in length.

“It was an impressive land movement,” said Stearns.

The slide blocked a road maintained by the city that is used as an emergency access to the Iron Horse development.

Reporter Jim Mann may be reached at 758-4407 or by email at jmann@dailyinterlake.com.