It’s extremely hard to know why.
I think for those of us in the Bay Area, we like to think that it was the early Shelter in Place order put into place ahead of the rest of the country. That’s one explanation. (This theory might be born out by this other head to head comparison)
Another is that we’re just not testing as much as New York.
Another is that we are a few days behind New York and we have yet to see the explosion of cases.
And, of course, because of New York City’s unique density it was the perfect storm. (Lovely Barcelona has been hit horribly hard also.)
“New York may just be three or four days in front of us. We’re going to see an increase in the number of cases here as well,” said Dr. Warner Greene, a senior investigator at the Gladstone Institutes in San Francisco who specializes in HIV but is studying the new coronavirus. “Days matter — they really matter. You think you’re fine, you’re absolutely fine, but this thing is just waiting to explode.
“But we went into shelter in place quicker; we got people apart quicker,” Greene said. “That could be a contributing factor to what we’re seeing in California now. And that’s why I think the whole country should be sheltering in place.”