Thursday, February 23, 2017

Chinook Thaw Floods Lower Clearwater and Other Rivers in the Region [otd 02/23]

The Lewiston Teller newspaper reported that on Sunday, February 23, 1879, "a regular Chinook visited us." The report provided no firm numbers, but the notorious Chinook wind can raise air temperatures by as much as 50-60ºF in a matter of hours.
Low ground flooded in Lewiston, ca. 1890.
U.S. Army Corps of Engineers.

In the day or so before, warm air had moved in from the coast. West of Lewiston, gushers from thawing in the high ground quickly raised the level of the Snake River. At the same time, the temperate air mass had rotated around south of town. Heavy runoff from those mountains had further swelled the river and, with no where to go to the west, had already caused high water around Lewiston.

The Chinook then flowed over the city and spurred similar melting in the ridges and plateaus to the east. The paper said, "On Monday the Clearwater was full from bank to bank with floating ice."

Creeks all across the area were correspondingly high, many carrying "much debris and small rocks." As a result, the paper said, "Roads were rendered entirely impassable by reason of the road beds being washed out in many places."

To make matters worse, the torrents carried away many smaller bridges. Only the desperate or foolhardy ventured about on horseback. In most areas, stagecoach traffic slowed to a crawl or came to a standstill – the Teller noted that the mails were almost universally late. Ice jams totally halted ferries trying to cross to the north: "The northern mail did not depart until Wednesday noon owing to ice in the Clearwater."
Four-horse stage. Library of Congress.

The Monday stage to Walla Walla tried to make it through, but a swollen creek overturned the vehicle at a crossing ten to fifteen miles out. The driver and a passenger finally struggled from the waters about 150 yards downstream. The lead horses somehow escaped the rigging and scrambled through. Some Indians rescued the other two horses and the coach about a third of a mile down

At Lapwai, the flood undermined the foundations of the saw and grist mill and swept it down the river. Not only did the water swallow up "a considerable quantity of wheat," it caught two men inside. The torrent carried the men downstream "about a mile and a half before they could be rescued, and their ultimate escape from death was almost miraculous."

Water spread into many occupied areas and a major irrigation canal near Lewiston was damaged. Debris filled everything that didn't simply wash away. A log "boom" – a floating barrier to confine a supply of timber – broke and hundreds of logs tumbled downstream, causing further damage.

Stories of impacts in other areas appeared for awhile afterwards. The Oregonian, in Portland, reported (March 8, 1879) heavy damage on that date along the Palouse River, to the north. Besides considerable property loss, a young man had been swept away and drowned. Another man, “with a bravery bordering on recklessness,” jumped into a rowboat and tried to save him, but failed.

As usual with such outbreaks, temperatures quickly fell back to normal and most of the flooding subsided in a few days. Unfortunately, the paper noted, "The whole section was damaged considerably and the loss will amount to many thousands of dollars."
Reference: [Illust-North]

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