Friday, June 03, 2016

Tornadoes don't seem to track to climate change, but wildfires and strong hurricanes may

Has climate changed increased the risk of natural disasters already?

It’s a pretty mixed picture.  But look at the history of tornadoes in the Washington DC area, as reported by the Washington Post.  One of them may have affected the War of 1812 (favorably).  They are pretty spread out throughout history.  /  One of the effects of a warming earth is that the polar latitudes warm up more.  So cold air masses that cause lift  and convection may actually be weaker.  Severe tornado outbreaks in the Midwest have always happened, but it seems that the really large storms in the southern plains may have increased.  In the mid-Atlantic area, Southern Maryland seems a little more vulnerable, as are some areas in particular relation to the Chesapeake Bay, which can add to wind shear in warm front-cold front sequences.  Oddly, in the mid-Atlantic, some of the most destructive storms occur in the fall or earlier in Spring, when cold fronts providing lift and shear may be stronger.

Tornadoes can occur almost anywhere in the US, and even on Earth.  The occur in Europe, and Britain.  They are very common in Argentina and some of Brazil. But improving modeling of future weather has increased awareness, especially on the Mid-Atlantic, that tornadoes can occur.  The threats probably happened when I was growing up, but we were not as aware of them, and trees in residential areas were smaller and younger and not as likely to fall in storms.

Have wildfires increased with climate change?  Anecdotally, it seems as though they have since the late 1980s. The vulnerability of some areas to a single lightning strike or cigarette butt is shocking.  But part of the problem is people building homes  in more remote areas that are exposed, especially in California, the Pacific Northwest, and in Rocky Mountain states.  Nevertheless, the inability of Fort McMurray, in the oil region of northern Alberta, to prepare itself with a brake line (no brush and trees) seems shocking.  Did people have the proper homeowner’s insurance?

What about flooding rains?  I lived in Dallas from 1979-1988, and summers were dry, from May to October.  I don’t recall any spells like the flooding in south and central Texas this year.  The worst day of tornado outbreaks happened in early May, 1979, right after I had moved there.  The weatherman on KXAS or WFAA was Harold Taft, and I recall the saying about barometric pressure that day, “that’s just too low.”

What about the frequency and intensity of hurricanes and cyclones or typhoons?  According to Time, the jury is still out.  But the gradual rise of sea level would seem to put more cities at risk.  We have had devastating Atlantic hurricanes in the past, like Hazel when I was a boy.  The threat of more superstorms (like Sandy) exacerbates the difficulty in maintaining mass transit particularly (NYC is having problems, just like DC, even if they haven’t gotten as much media attention lately, with many Sandy-related repairs to be done yet).

Picture: Tupelo, MS damage, my trip, May 2014

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