1. History
    Late January 

2. Effect and aftermath
    Oregon  California  North Coast  Central Valley and beyond  Elsewhere 

3. See also

4. References

5. External links

The Christmas flood of 1964 was a major flood in the Pacific Northwest and some of Northern California between December 18, 1964, and January 7, 1965, spanning the Christmas holiday.^[1]

Considered a 100-year flood,^[2]

it was the worst flood in recorded history on nearly every major stream and river in coastal Northern California and one of the worst to affect the Willamette River in Oregon. It also affected parts of southwest Washington, Idaho, and Nevada.^[1][3]

In Oregon, 17 or 18 people died as a result of the disaster, and it caused hundreds of millions of dollars in damage.^[3] The flooding on the Willamette covered {{convert|152789|acre|ha|sigfig=6}}.^[4]

The National Weather Service rated the flood as the fifth most destructive weather event in Oregon in the 20th century.^[5]

California Governor Pat Brown was quoted as saying that a flood of similar proportions could "happen only once in 1,000 years," and it was often referred to later as the Thousand Year Flood.^[1] The flood killed 19 people, heavily damaged or completely devastated at least 10 towns, destroyed all or portions of more than 20 major highway and county bridges, carried away millions of board feet of lumber and logs from mill sites, devastated thousands of acres of agricultural land, killed 4,000 head of livestock, and caused $100 million in damage in Humboldt County, California, alone.^[9][10]

History

An atypical cold spell began in Oregon on December 13, 1964, that froze the soil, and it was followed by unusually heavy snow.^[3][6]

Subsequently, an atmospheric river brought persistent, heavy, warm rain.^[3][6] The temperature increased by {{convert|30|to|40|F-change|C-change|sigfig=2}}. This melted the snow, but left the soil frozen and impermeable.^[6] Some places received the equivalent of a year's rain in just a few days. Albany received {{convert|13|in|mm|sigfig=2}} of rain in December, almost double its average December rainfall of {{convert|7|in|mm|sigfig=1}}.^[3] Detroit recorded an extra {{convert|18|in|mm|sigfig=2}} of rain, and at Crater Lake, where the average normal December rainfall is {{convert|12|in|mm|sigfig=2}}, there was over {{convert|38|in|mm|sigfig=2}} of rain.{{Clarify|date=September 2014|reason=Is 38 inches rain equivalent or was it really all rain?}}^[3] As rivers and streams overflowed and the soil became saturated, mudslides occurred, roads closed, and reservoirs overflowed.^[3] Many towns were isolated.^[3] By the end of the flood, every river in Oregon was above flood stage, and more than 30 major bridges were impassable.^[3]

Late January

Heavy warm rain and melting snow caused more flooding in late January 1965, after the waters had begun to recede from the December flood.^[1] More mudslides occurred in places that had withstood the December flooding, and there were more deaths.^[1] Many streams in the northern San Joaquin Valley reached higher flows than they had in December.^[7]

Effect and aftermath

Oregon

The Christmas flood of 1964 was "the most severe rainstorm to ever occur over central Oregon, and among the most severe over western Oregon since the late 1870s", according to the National Weather Service office in Portland.^[5]

Some of the worst mudslides occurred in the Mount Hood Corridor, and one man died in a mud and debris avalanche near Rhododendron that destroyed 15 houses.^[3] Other deaths occurred from drowning and electrocution, and one man died when the new John Day bridge collapsed.^[1][3]

On the Oregon Coast, downtown Reedsport was flooded with {{convert|8|ft|m|sigfig=2}} of water, and in Coos Bay, a massive logjam contributed to severe flooding.^[3] The ports at Gold Beach and Brookings were destroyed.^[3]

At Oregon City, Willamette Falls was unrecognizable as a waterfall, and the city was flooded by several feet of water.^[3] In Portland, the lower deck of the Steel Bridge was underwater and had also been hit by a log raft consisting of around 1,000 logs.^[3] The impact of the raft severely damaged the Hawthorne Bridge, closing it for a year.^[3] At {{convert|12|ft|m|sigfig=2}} above flood stage, the flooding of the Willamette River at Portland in 1964 was second only to the 1948 flood that wiped out Vanport City.^[3] At its peak, the water was at the top of Downtown Portland's seawall.^[1]

The Southern Pacific (SP) rail line between Portland and San Francisco was out of service for eighteen days as crews repaired damage from landslides near the {{convert|4885|ft|m|adj=on}} Cascade Summit; and the parallel Willamette Pass highway was blocked for several days. Salt Creek washed out {{convert|25|mile|km}} of Oregon Route 58 and undermined the SP viaduct footings. Landslides covered {{convert|700|ft|m}} of SP track near Oakridge, and swept away {{convert|130|ft|m}} of the Noisy Creek bridge {{convert|20|mile|km}} north of Crescent Lake. The Willamette River washed out {{convert|300|ft|m}} of SP track between Portland and Albany.^[8]

California

Starting on December 21, intense downpours all across Northern California caused numerous streams to flood, many to record-breaking levels. California Governor Brown declared 34 counties in the region disaster areas.^[1][7] Together, Del Norte, Humboldt, Mendocino, Siskiyou, Trinity, and Sonoma counties sustained more damage than the other 28 counties combined.^[7] Twenty-six U.S. Geological Survey (USGS) stream gauges were destroyed.^[7]

North Coast

The Eel, Smith, Klamath, Trinity, Salmon, and Mad rivers, as well as other rivers and large streams, all went well beyond flood stage and peaked nearly simultaneously around December 21 and 22, breaking previous records (notably those set in the "hundred year" flood of 1955 in most cases).^[1][7] Sixteen state highway bridges were destroyed in California's 1st congressional district, most of them on Highway 101, and another ten county bridges were destroyed in Humboldt County.^[7] The flood destroyed {{convert|37|mile|km}} of track with multiple stream and river crossings of the Northwestern Pacific Railroad through the Eel River canyon, the region's only major railroad.^[9]

Many communities of Del Norte and Humboldt counties suffered massive power outages and were left isolated (or completely cut off from the rest of the state for a period), including the region's larger populated areas around Humboldt Bay, such as Eureka and Arcata, despite the fact that those cities were located on higher ground and not in the path of raging rivers. Unfortunate riverside communities like Klamath, Orleans, Myers Flat, Weott, South Fork, Shively, Pepperwood, Stafford, and Ti-Bar were completely destroyed by flood waters; some of them were never rebuilt and none regained their former status. Metropolitan, Rio Dell, and Scotia were significantly damaged.^[7] The Pacific Lumber Company sawmill at Scotia lost 40 MMFBM of logs and lumber washed downstream.^[9] Crescent City, still recovering from the tsunami created by the 1964 Alaska earthquake only nine months earlier, also suffered from the floods.^[7]

Over {{convert|550|mm|in|disp=flip|sigfig=2}} of rain fell on the Eel River basin in a span of two days. By December 23, {{convert|752000|ft3/s|m3/s|sigfig=3}} of water rushed down the Eel River at Scotia (still upstream from the confluence of the Van Duzen River),^[10]

Just under {{convert|200000|ft3/s|m3/s|sigfig=3}} of water flowed down the South Fork Eel River alone, causing severe damage along its entire length.^[10] Every single stream gauge on the Eel River was destroyed.^[7] The flood crest at Miranda was {{convert|46|ft|m|sigfig=2}}. Signs were later placed on top of tall poles to mark the unusual height of the water.^[12]

The Smith River, located in Del Norte County near the Oregon border, reached flows of {{convert|228000|ft3/s|m3/s|sigfig=3}} at Hiouchi,^[13]

easily surpassing the 1955 flood's previous record of {{convert|165000|ft3/s|m3/s|sigfig=3}}.^[7] The town of Gasquet received {{convert|26.6|in|mm|sigfig=3}} of rain over an eight-day period, and Crescent City received {{convert|9.2|in|mm|sigfig=2}}.^[7]

The Klamath River reached flows of {{convert|557000|ft3/s|m3/s|sigfig=3}},^[14]

submerging the town of Klamath under {{convert|15|ft|m|sigfig=2}} of water.^[7]

The Trinity River, one of the Klamath's largest tributaries, also flooded and wrought destruction along its length. The Trinity, however, did not break the 1955 flood's records because of the newly constructed Trinity Dam, which stored {{convert|372200|acre.ft|m3|sigfig=4}} of runoff from the storm.^[7] Nonetheless, an impressive {{convert|231000|ft3/s|m3/s|sigfig=3}} of water rushed down the river at Hoopa.^[15]

Between December 20 and December 26, a staggering {{convert|10390000|acre.ft|km3|sigfig=4}} of water flowed into the Pacific Ocean from the combined rivers and streams on the North Coast.^[7]

Central Valley and beyond

In the Central Valley, the Yosemite Valley was flooded, and residents of Yuba City were evacuated.^[1] Many streams reached record flood stages, including the Feather River, Yuba River, American River, Cottonwood Creek, and Butte Creek. The flood caused the uncompleted Hell Hole Dam on the Rubicon River to fail, sending even more water downstream.^[7] In total, {{convert|375000|acre|ha|sigfig=3}} of the Central Valley was flooded.^[7]

Elsewhere

In southwest Washington, rising rivers threatened Centralia and Longview–Kelso^[1] and closed Interstate 5 and all railways at flooded Kalama for over a week.{{citation needed|date=December 2010}} In Nevada, the Truckee River threatened Reno.^[1]

See also

• Great Flood of 1862
• Willamette Valley Flood of 1996
• Christmas flood of 1717

References

External links

• History of the Christmas week flood from Salem Public Library
• The '64 flood story from Mail Tribune
• Images of the 1964 flood from Salem Public Library
• Images of the 1964 flood in Corvallis from the University of Oregon Library digital archives
• Images of the 1964 Eel River Flood near Van Arsdale Reservoir from the Potter Valley Irrigation District

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