Bringing over 50 inches of rain in less than five days, Hurricane Harvey caused $100 billion in damage and dozens of deaths. The devastation wrought by the powerful hurricane was, officials say, exacerbated by waters warmed and expanded by climate change.

Is Southern California, also a region with a history of deadly flooding, more vulnerable now than it has been in the past? Scientists and engineers say yes. The effects of a warming planet and resulting sea-level rise are already upon us and will continue to worsen.

“The number of high-level rain events are likely to increase from climate change,” said Adam Rose, a research professor at USC who has studied the economic consequences of an extreme storm hitting the California coast. A severe storm would be devastating. “The loss estimates for a severe atmospheric storm are larger than our estimates for a catastrophic earthquake,” Rose said. “It would affect so much of the state.”

A 500-year storm last hit California in 1861. If another 500-year storm hits, the cost of property damage to the state in building losses, drinking water systems and other infrastructure damage would be more than $100 billion over five years, according to Rose’s research. The state’s most vulnerable areas in a major storm are densely developed, flood-exposed cities in Los Angeles, Orange and Santa Clara counties, and much of the state’s Central Valley. The most vulnerable areas in L.A County are low-lying Malibu, Venice, Marina del Rey, and Belmont Shore. Vulnerable communities in Orange County include Seal Beach, Sunset Beach, Huntington Beach and Newport Beach.

But storm impacts will vary region-by-region depending on local conditions and preparations such as drainage, seawalls and emergency response systems. Public works departments in L.A. and Orange counties maintain extensive flood-control systems to protect the region from anticipated weather events. But the areas most at risk across Southern California are the coastal communities that rely heavily on cash-strapped small governments to maintain and modernize infrastructure to withstand major storm surges. These increasingly dense coastal communities are often left vulnerable with inadequate storm drain systems and ill-equipped emergency evacuation routes. Jay Lehr, science director of the Heartland Institute says cities should take heed and ensure that their drainage and emergency-response systems can handle a massive storm such as Hurricane Harvey.

Source: Daily Breeze