Likely seawater inundation of Bay Area from an intense 100-year storm (1% probability in any given year) today (blue) and with 150 cm sea level rise (red). US Geological Survey, 2010

By Jeffrey F. Mount, geology professor and founding director of the UC Davis Center for Watershed Sciences

As you read this today, Hurricane Sandy is colliding with cold air from Canada and creating an impressive storm in the Northeast.

Strong onshore winds and an intense low-pressure system are causing storm surges as high as 13 feet in Lower Manhattan, threatening to swamp the subway system. On the land, 5-10 inches of rain is flooding creeks and rivers and overwhelming stormwater systems.

This combination of too much runoff heading to the ocean and too much water surging in from the ocean will continue to cause dramatic coastal flooding this week. Worse, the combination is centered on the most densely populated part of the Northeast coast, setting the stage for maximum economic damage and disruption.

The San Francisco Bay Area business community should be taking notes. This trifecta of high tides, storm surge and intense rain is also a Bay Area scenario. Scientists and a host of government agencies have been warning about such an event for years.

It may not appear so on a map, but the Bay Area has half of California’s shoreline. Unlike the rest of the state’s coast, most of that shoreline is along reclaimed lowlands that are prone to flooding from the bay and surrounding creeks – the same as waterfront cities in New York and New Jersey.

A major storm in the Bay Area would put more than 140,000 people at risk of serious flooding, along with $30 billion worth of public assets that include the Port of Oakland, two major airports and 800 miles of roadways.

Though they are not hurricanes, California experiences its own form of tropical storms known as the Pineapple Express. Scientists call these storms “atmospheric rivers.” They tap into energy and moisture from the tropics, producing winds and rainfall rates that match the fury of Hurricane Sandy. When these storms combine with high tides, much as Sandy has, they can cause widespread flooding along the coast in the Bay Area.

Many regional and local planning agencies have sounded the alarm: the Association of Bay Area Governments; the San Francisco Bay Conservation and Development Commission; the National Oceanic and Atmospheric Administration; the Bay Area Council; the Metropolitan Transportation Commission; CalTrans; the California Ocean Protection Council; the Environmental Protection Agency; and the San Francisco Bay Regional Water Quality Control Board. In addition, all nine Bay Area counties have identified this flooding scenario as significant potential hazard in their general plans.

Meanwhile, the business community has been passive – ensuring nothing will get done. This may be because so much of the Bay Area discussion on flood risk has been in the long-term context of sea level rise resulting from climate change.

Yet all of the flood studies have shown that the risk today is high. Sea level rise will only make matters worse.

Bay Area business leaders should map this week’s whopper storm in the Northeast onto their own coastal turf. As California’s version of Sandy rolls in and overwhelms the Bay Area’s meager flood defenses, businesses like Oracle, Cisco, Intuit, Lockheed Martin, Google and Facebook will find themselves unable to do business, possibly for a long time.

It makes good business sense for these businesses to move aggressively to manage their coastal flood risk.

Further reading

Association of Bay Area Governments interactive flood maps.

Adapting to Rising Tides, a collaborative effort to plan for big storms and rising sea levels, led by the San Francisco Bay Conservation and Development Commission and the National Oceanic and Atmospheric Administration.

Cloern, J.E., N. Knowles, L.R. Brown, D. Cayan, M.D. Dettinger, T.L. Morgan, D.H. Schoellhamer, M.T. Stacey, M. van der Wegen, R.W. Wagner, and A.D. Jassby, 2011, Projected evolution of California’s San Francisco Bay-Delta-River System in a century of climate change, PLoS ONE, 6

Hanak, E., J. Lund, A. Dinar, B. Gray, R. Howitt, J. Mount, P. Moyle, B. Thompson, 2011, Managing California’s Water: From Conflict to Reconciliation. San Francisco, Public Policy Institute of California. 482 p.

Heberger, M., H. Cooley, P. Herrera, P.H. Gleick, and E. Moore, 2009, The Impacts of Sea-Level Rise on the California Coast, California Climate Change Center, CEC-500-2009-024-F, Sacramento, California, 101 pp.

Knowles, N., 2010, Potential inundation due to rising sea levels in the San Francisco Bay Region. San Francisco Estuary and Watershed Science.

NRC (National Research Council), 2012, Sea-level Rise for the Coasts of California, Oregon and Washington: Past, Present and Future. Committee on Sea Level Rise in California, Oregon and Washington. National Academies Press.