Overview

The 2006 Water Year began with generally mild temperatures (most stations reported above-normal values) and wet conditions (mostly above-normal precipitation). All in all, October was a very pleasant autumn month, but watch out – here comes winter!

Table 1 is a summary of monthly averages and totals at selected stations throughout the state. Table 2 lists daily temperatures and precipitation for most of the locations listed in Table 1. In Table 3, monthly and seasonal precipitation totals throughout the state are listed.

Basin Summary

Here is a summary of water indicators at the end of the month, by river basin:

n.a. Not available
(1) Percent of normal October precipitation, from NOAA Cooperative sites
(2) Percent of normal October precipitation, from Natural Resources Conservation Service (NRCS) SNOTEL sites
(3) Percent of normal October stream flow, from U.S. Geological Survey (USGS)
(4) Surface Water Supply Index, from NRCS (-4 = very dry, 0 = normal, +4 = very wet)

Forecasts
The Climate Prediction Center’s (CPC) forecasts for November-January appear below. Temperatures for all of Oregon are likely to be above normal. Precipitation probabilities suggest an equal probability of below-, near-, or above-normal precipitation. CPC also says:

Tropical influences – including ENSO and tropical 30-60-day oscillations are currently neutral or weak and are expected to have little or no impact on the climate in the near-term. Trends are used in this forecast. Their impacts are especially large in forecast leads beyond 0.5 months. The impact of the NAO [North Atlantic Oscillation] this winter is uncertain for at least two reasons. First- the NAO is currently near its neutral phase. Also – we are currently able to predict only a small fraction of the climate variability associated with the NAO. Research is being conducted with the aim of improving the use for prediction of all of these factors.

Oregon Climate Service predicts above-normal precipitation and normal temperatures. For the three-month period ending in January, we predict above-normal precipitation and slightly above-normal temperatures.

43 Years ago this month: the Columbus Day Storm
October 12 passed without fanfare this year. It wasn’t even “Columbus Day” – that honor went to October 10 because it was a Monday. But Northwest weather nuts remember that date every year, and locals who lived here in 1962 will never forget the “Columbus Day Storm.”

My synopsis of the storm:

When it comes to wind storms in Oregon, the Columbus Day storm stands alone. Nothing before nor since has matched the intensity and damage of that storm, although a few have come close. The "storm" was actually three storms in quick succession. The first formed as a trough off the coast of Oregon on the 11th; it moved northward, and then northwestward, and began to taper off on the 12th. The second (and most destructive) storm formed from the remnants of Typhoon Freda, which moved northeastward from the Philippines, nearing the west coast early on the 12th.

As it neared California, the storm nearly stopped moving, intensified, and began to slowly move northward just off the coast. As it moved, it wreaked havoc from northern California to British Columbia.

The storm reached the Oregon coast on the afternoon of the 12th. The central pressure of the storm dropped lower and lower, finally reaching 28.42 inches. Winds were strong along the coast, but even stronger inland. At Mt. Hebo in the Coast Range west of Salem, measured wind speeds reached 131 mph before the anemometer was destroyed by the winds. On the Morrison Street bridge in Portland, winds gusted to 116 mph (in Naselle, Washington they reached 160 mph). Trees, houses, and power lines were destroyed throughout the state; in some cases residents were without power for 2 to 3 weeks. Giant towers holding the main power lines into Portland (over 500 feet high) were knocked down. The Red Cross estimated that 84 homes were completely destroyed, 5000 severely damaged, and 50,000 moderately damaged. 23 people died in Oregon alone, and damages were estimated at $170 million.

Locally, something remarkable happened. Corvallis Airport collected hourly observations at that time, via a human observer (weather data are now collected on an automated station). On October 12, the wind speeds got higher and higher, finally peaking at 110 (127 mph) at 4 p.m. Just below that, where the next several observations would go, are several blank lines and the words “Abandoned Station” noted at 4:15. A few lines farther down, just before observations began again, the observer wrote that several readings were “unreported due to power failure and instruments demolished.” That brings to mind several questions:

(1) how much stronger did the winds get after the anemometer was destroyed?
(2) where did the observers go?

To (1) my guess is that it didn’t get much stronger, since most Valley sites seemed to observe their maximum winds at about that time. Question (2) is a different matter, and I’m clueless. I wonder if there was a cellar to hide in. Surely they wouldn’t go outside and drive away, would they? I may never know. But I do know this: the Columbus Day Storm was by far the biggest and most significant wind storm the Northwest ever had. My friend Wolf Read told it this way: In the Willamette Valley on Columbus Day, the lowest of reported maximum wind gusts was Eugene at 86 mph (Salem was 90, Portland 116 and Troutdale 106). No other storm has had a SINGLE location that reached 86 mph in the Valley.

I have placed a scanned copy of the Corvallis Airport observation form, along with several pictures of storm damage, on the Oregon Climate Service Web site at
http://www.ocs.orst.edu/pub/reports/columbus/
Several pictures appear on the below.

A damaged car on the Oregon State University campus after being hit by a falling tree.

The Van Buren Street bridge, Corvallis, damaged by a falling tree

Oregon Climate Service

George H. Taylor, Oregon State Climatologist

Wayne P. Gibson, Programmer/GIS mngr.

Eileen Kaspar, Research Assistant/Manager of Data Services

Melanie Mitchell, Undergraduate Assistant

Wolf Read, Undergraduate Assistant

Emily Gibson, Student Assistant

Cadee Hale, Publications Assistant

Sara Joos, Student Assistant

Sean Daly, Student Assistant

Kirk Borgerding, Undergraduate Assistant

Kelsey Kuykendall, Undergraduate Assistant

Oregon Climate Service, Strand 326,                             	     Phone: (541) 737-5705  
Oregon State University                                                      Fax: (541) 737-5710   
Corvallis, Oregon  97331                                                     E-mail: oregon@coas.orst.edu   
                                                                             Web: http://www.ocs.oregonstate.edu