Fast Riser

Smith’s surge in velocity was dramatic

Debris floats in the rapidly rising Smith River, above and below, as it reached its crest Thursday near flood stage. Bryant Anderson/ Del Norte Triplicate

In 38 rain-soaked hours, the Smith River’s flow surged almost a hundredfold.

At 1:30 p.m. Thursday the Smith crested at 28.4 feet in Hiouchi. Its height was only 6.54 feet at 12:01 a.m. Wednesday.

During the same period, the river’s flow increased from 1,100 cubic feet per second to 109,000 cfs.

Crescent City had 2.45 inches of rain Thursday, breaking the record for the date of Jan. 19 of 1.93 inches in 1964.

The rain caused three slides on South Fork Road including one 13 miles up near Goose Creek, a partial slide 11 miles up, and another slide at Surprise Falls, two miles up, according to Big Flat resident Chuck Blackburn. The California Highway Patrol said there was no shortage of downed trees, limbs and the occasional rocks to be cleaned up from the storm.

Blackburn said the South Fork near his house was “roaring” on Thursday.

“You can hear the boulders rumbling in the canyon as they flow like peas down the river bed,” he said.

Blackburn said Friday afternoon he had recorded 18 inches of rain­fall since Tuesday in Big Flat. The National Weather Service recorded 10.36 inches in Gasquet, 9 inches at the Dr. Fine Bridge and 6.05 inches at the airport from midnight Wednesday to midnight Friday.

The star of the show, however, was the raging river.

Bryant Anderson/ Del Norte Triplicate

The Smith had dropped to 16.78 feet with a flow of 25,800 cfs by 3 p.m. Friday, but the river started to rise again after the county received at least another inch of rain. By 5:45 p.m. Friday the river was up to 17.74 feet, with a flow of 17.67 cfs.

The rapid rise of the Smith was a result of three factors: heavy rainfall, the river basin’s geological makeup and the layout of the river and its tributaries.

Let’s start with the rain.

The mountains of Del Norte are the first piece of land that many storms  reach when coming across the Pacific.

“(The storm systems) hit these mountains and get pushed up, and when the air goes up, it can’t hold as much water, so it rains,” said Michael Furniss, a hydrologist with the U.S. Forest Service, who has worked on the Smith for years.

 “We have the highest rainfall in any basin in the continental U.S.,” said Grant Werschkull, executive director of the Smith River Alliance. Werschkull described the quick rise and drop of the Smith this week as “flashy.”

The second factor is where the rain falls: on rocky ground. The entire basin is very rocky and some parts are packed with heavy metals like cobalt, chrome and copper, especially around the North Fork, Werschkull said.  Rocky ground absorbs less water, so water quickly reaches the Smith.

The super-charged middle fork of the Smith River rushes beneath a bridge Thursday. Bryan Anderson/Del Norte Triplicate

The other factor is the layout of all of the Smith’s forks and tributaries.

Rain falls on mountainsides, then flows down to a fork or a creek, eventually reaching the main stem.  All of the creeks and forks feed into the main stem at relatively the same time, creating those “flashy” flows.

Furniss said the palmate (resembling a finger-spread hand) design of the watershed will “synchronize the flows so they all hit the main fork at the same time.”

Although the NWS predicted that the Smith would reach flood stage Thursday morning, the river crested just before it reached 29 feet at the Hiouchi gauge. The December drought could have helped prevent flooding, Furniss said.

“The flooding would have been worse if we had not had that dry period,” Furniss said, adding that if a similar system hits Del Norte now, we would probably have more flooding.

Anyone watching the river on Thursday or Friday saw massive amounts of trees and limbs float by. All of that woody debris is good for fish habitat, said Joêl Benegar, who has  her master’s degree in watershed management from Humboldt State University. Benegar studied the relationships of wood, rivers and fish for her thesis statement.

“River, sediment and wood are all one system,” Benegar said. “They create the habitat the salmon need.”

A house on North Bank Road is surrounded by water. Bryant Anderson/Del Norte Triplicate

Benegar and Werschkull had plans to kayak the main stem of the Smith today, and perhaps raft one of the smaller creeks Sunday.  Those plans were fluid, since it’s still raining, and “predictions keep changing every hour,” Benegar said.