Monday, December 22, 2014

Rain? In a Rain Forest? Exploring California and Oregon on the 50th Anniversary of the Biggest Flood Ever

Humboldt Redwoods State Park, California
It starts with little cascades like this...
Humboldt Redwoods State Park
That grow into brooks like this, repeated thousands of times over...
Prairie Creek, Redwood National Park, CA
Which leads to this...
Prairie Creek Elk viewing area, Redwood National Park
Our Christmas travels took us into the northwest of California and into Oregon, and as luck would have it, we drove right into a continuation of the storms that have been pounding the west coast this month. At home, we've already received more precipitation than all of last year's horrific drought totals. As we drove north on Highway 101, we watched the rain falling for hours, and soon, every waterway was filled with muddy water. It may be the first truly cleansing flows these channels have had in some time.
Eel River at Phillipsville
I don't think any records are in danger of being broken, but with the anemic levels of precipitation over the last three years, it was nice to see these rivers brimming with water. Now that I have access to some data, I am finding some impressive numbers stacking up. The Klamath River is flowing at 95,500 cubic feet per second, 961% of normal daily flow for this time of year. The Smith River reached 65,000 cfs for awhile (about 20 times normal), and Redwood Creek was around 11,900 cfs, about ten times normal.
Eel River, CA
The ultimate for our day was the Umpqua River near Roseburg, Oregon. Just downstream at Elkton, it is flowing at 131,000 cfs, a bit above flood stage. Compare to three or four days ago when it was flowing at about 5,000 cfs.
Umpqua River at Roseburg, Oregon

Umpqua River at Roseburg, Oregon

 A year ago at this time, the river was pretty much a pool...

Here is how hydrologists see these rivers, with a graph that shows the discharge (cubic feet per second) over a week's time. The effect of the latest storms is clear.
 Graph of

The water flows will undoubtably drop off over the next few days, but it is impressive to see what the rivers can do. Today is the 50th anniversary of the worst floods ever in the region, the 1964 Christmas Floods. In that flood there had been a cold snap where a great deal of snow had accumulated and the ground was frozen. Then, over several days around Christmas, a Pineapple Express storm dropped prodigious amounts of rain, which melted the snow, but did not melt the soil, so little of the rain was absorbed into the ground. Around three dozen people were killed, and several dozen villages were completely erased. Many dozens of bridges were destroyed, and numerous other towns were cut off for weeks.

Compare the numbers:

Klamath River today, 95,500 cfs, in 1964, 565,000 cfs.
Eel River today, 40,000 cfs, in 1964, 750,000 cfs.
Rogue River (Oregon) today: 23,500, in 1964, 200,000 cfs.

By some estimates, such a flood is estimated to happen maybe once in a thousand years.


Lockwood said...

Those are some incredible numbers... honestly glad I wasn't here to experience them!

Lockwood said...

If you're looking for a nice day trip, it's about an hour and fifteen minutes from Florence to Sunset Bay, Shore Acres, and Cape Arago, near Charleston. My favorite area along the coast, and that's very high praise. Covered Shore Acres 7/22-8/10 in Geo 365 last year, and Sunset Bay 2/11-2/17 of the series.