SAN FRANCISCO – From gauging water levels behind dams, insuring the durability of levees, to working with local communities, the U.S. Army Corps of Engineers in San Francisco has embarked on an extensive effort to prepare the Bay Area and its network of waterways, wetlands and reservoirs for the arrival of an El Nino weather pattern which forecasters warn could bring prolonged periods of heavy rain, mudslides and flooding to a region more accustomed to years of drought.
“One of the things that keeps me up late at night is the idea with the El Nino that we could have an emergency on our hands and how we would react not only as an agency but collectively with the partners we have with us,” Brig. Gen. Mark Toy, commander of the Corps’ South Pacific division told a recent flood preparedness workshop, as many in the Bay Area began preparing for the worst by replacing roofing and inspecting property that could be vulnerable to prolonged periods of heavy wind and rain. “We’re all watching the weather very closely on a daily basis and seeing the things that could affect us,” Toy said.
An El Nino in 1983 brought 13 inches of rain to San Francisco during the month of February alone. This year, forecasters are warning that the Bay Area as well as the rest of California should prepare for an even stronger storm pattern beginning this winter and lasting through April. El Ninos form when large amounts of heat are released into the atmosphere from a warmer than normal Pacific Ocean, triggering heavy rains that have caused devastating floods and mudslides. This year, ocean temperatures are even warmer-- and sea levels even higher -- than during the last strong El Nino in 1997-98. “We’re well above what we could consider El Nino conditions,” National Weather Service hydrologist Mark Strudley told the flood preparedness workshop, organized by the Corps’ San Francisco district to help prepare communities for what looks likely to be coming. “There’s a 95 percent chance we will have El Nino conditions persisting throughout the winter,” he warned.
In August, Lt. Gen. Thomas P. Bostick, the Corps’ commanding general and chief of engineers visited the Bay Area in part to review flood preparation and what the agency could do if called upon by state and local authorities to assist in the event of weather-related emergencies. “As the Corps of Engineers, we are mostly concerned with the flood obviously through our missions and authorities,” said Gen. Toy, who this week inspected Corps-run dams at two large reservoirs at nearby Lakes Sonoma and Mendocino while engineers in the San Francisco district worked to conduct levee screening assessments and insure that adequate flood control infrastructure is in place throughout the region.
“What we hear often from the community is ‘what could I have done to better prepare’,” said Paul Schimelfenyg, a civil engineer with the Corps in San Francisco. He recalled how previous El Nino’s caused levees across the region to be breached. While last year did not see an El Nino, 20 inches of rain did fall during a 24 hour period, causing the Novato Creek levee in Marin County to fail.
Compounding this year’s El Nino threat is a four year drought that has left hillsides and stream beds extremely vulnerable to mudslides, reminding many in the Bay Area of the ’97 El Nino which was blamed for 17 deaths and was estimated to have caused more than half a billion dollars in property damage, no doubt why San Francisco District Commander Lt. Col. John Morrow has made preparing for all possibilities a priority. “We’ve heard a lot about El Nino and the predictions are looking ominous and we have to be prepared for the worst.”