Theme for 1997:
Precipitation and Flooding of 1997

June 28, 1997
Sierra College, Rocklin, CA

Speaker Presentations

A Visual Look at the Flooding of 1997 and 1986

Doug Powell
Instructor of Geography
California State University, Sonoma and University of California, Berkeley
Berkeley, CA
  • [Presentation not available]


Doug Powell shared his collection of color slide photographs. His images gave us a better appreciation for the physical scale of the impacts of such extreme flood events. The amount of land inundated by flood waters and the damage caused by human decisions to build in floodplains can best be understood by seeing his pictures. Unfortunately, the cost to reproduce color slides was beyond the budget limitations for producing these Proceedings. You just had to be there …

The Great New Year's Flood of 1997 in Northern California

Maurice Roos
Chief Hydrologist
California Department of Water Resources
Sacramento, CA


The New Year's flood of 1997 was probably the largest in the 90-year Northern California record which begins in 1906. It was notable in the intensity, volume of flood water, and the areal extent from the Oregon border down to the southern end of the Sierra. Many new flood records were set.

East Slope Sierras Precipitation and Flooding of 1997

Dan Greenlee
Natural Resources Conservation Service
US Department of Agriculture
Reno, NV


I'm going to give some information on precipitation amounts, snowfall amounts, damages, etc., and then I've got some vidEODapes on the actual flooding in Nevada. I'm going to primarily be talking about the Tahoe, Truckee River, Carson, and Walker River Basins. Those are the major ones over on our side.

Meteorology of January 1997 Floods

Bill Mork
State Climatologist
California Department of Water Resources
Sacramento, CA


Today, we're going to talk about the winter a little bit, the heavy rain period. Wettest back-to-back months of the century in most of the Northern Sierra (not everywhere in California). You can take a look here, and we're talking about the recent Water Year 1997. Here's the big month of December, and there's January. The other years, as you see, Water Year 1996 in, kind of this rust, and then Water Year 1995 in the green.

We're going to be talking about the major storm first of all. You had the eight day period we talk about historically as one of the big ones of the century. 26 December through 2 January, and then also, very briefly, about the one later on in the month, 20-29 January. That was bigger in the valley as Maury Roos mentioned. The first one, obviously, is the one of great interest.

National Weather Service Operations During 1997 Floods

Jan Null
Lead Forecaster
San Francisco Bay Area Office
National Weather Service
Monterey, CA


I'm going to do sort of like Bill, sort of a two-part show here since with all the interest in El Niño I'm going to do my first half about the flood of 1997, and then talk a little bit about all the things Bill said I should talk about.

A lot of this information has been touched on already. As we went into the Christmas break we had the very heavy precip and snow in the Sierra. Then we had the forecast of a big ridge on through the holidays. Like Bill has done, we put out special weather statements about all the dense fog, everyone drive carefully etc. Didn't mention a word or anything about rain.

On Christmas Day we started seeing the models beginning to flip flop and, as we heard from Maury Roos, sort of the classic-type of recipe for flooding events — had a recent very heavy amount of snow down to real low level. So you bring all this warm rain in on top of it.

One Hundred Years of Extreme Rainfall Data

James D. Goodridge
Califomia State Climatologist, Retired
Mendocino, CA


This study started as a search for California rain records with 100 years of daily rain data. Seventy-six records were found which were nearly complete. They covered the entire state and the years 1898 to 1997. The rain records for this study are listed in Table I. A further object of this study is to evaluate long-term trends in flood-producing rainfalls and the forces that influence them. Still another objective of this study is to celebrate 100 years of climatological data — which publish the efforts of a vast corps of volunteer weather observers — and the National Weather Service who administer it.

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