L.A. County is No. 1 in natural disasters

Social scientists and philosophers sometimes talk about the McNamara fallacy: making an argument using only quantitative observations — measurements — and discounting context.

Case in point: various Los Angeles County statistics — human, economic, geographic — are often cited as being the “most,” the “highest,” the “largest number” of any county in the nation.

But Los Angeles County with our 10 million people is the largest county in the nation. So what’s surprising is to find a category in which we aren’t the leader. It’s obvious: more people to choose from.

L.A. County is not the nation’s largest in territory; that’s neighboring San Bernardino. But Los Angeles’s topography — from near-barren high desert to sub-tropical Pacific Ocean beaches, from snow-topped, forested mountain ranges to densely populated urban canyons where mountain lions still roam — is surely unprecedented on Earth in its variety.

So it shouldn’t be a stretch to know that our county is also unprecedented in its vulnerability to natural disaster. And FEMA last week confirmed this: ranking counties on vulnerability to 18 natural disasters, we’re No. 1. We’re especially vulnerable to deadly flooding when there’s a deluge in our foothills, even more than we are to the Big One earthquake in our future.

Just because it shouldn’t be news that Angelenos live on shaky ground doesn’t mean that such an official ranking doesn’t give pause. It also gives rise to the natural human tendency to “do” something about it. And we have done. While Los Angeles can’t stop dangerous Santa Ana winds, it can and does ban combustible shingles for housing and mandates brush clearance to fight wildfires. After the floods of 1938 that killed more than 110 people, the county and the Corps of Engineers created perhaps the largest water-management system in the world. If anything, it was overbuilt, and requires the humanizing that Friends of the Los Angeles River have created and as architect Frank Gehry proposes. Our building codes are strong, but we still need to catch up to Mexico and Japan by installing the seismic-early warning systems already cheaply available.

At least tornadoes are rare here. We count our blessings as we love L.A.