Saturday, July 27, 2019

Cape Cod Tornado vs Cape Cod Hurricane


The tornadoes that huffed and puffed and blew down parts of Yarmouth and Harwich were more outlier than typical. Cape Cod doesn't get a lot of those.

We don't get a lot of hurricanes, either... but we get a lot of them when compared to tornado activity.

The tornadoes we had this week were of the F1 variety, with winds around 110 mph. People who are into storms know that F1 is towards the bottom of the scale. That can seem disappointing.

While I don't live in Iowa or anywhere like that, I'm not 100% sure that an F1 would even get on the news there, especially where it may just wreck Earl's cornfield before dissipating.

Of course, it would only take a short ride through parts of Harwich to remind a person of just what an F1 can do.


The 110 mph winds of an F1 would be a strong Category 2 hurricane. We don't get many of those here, but we do get them. It's tempting to say "every 25 years or so," but if you study it some, you'll see a more random pattern

We had a bunch in the last 100 years, but no trend shows itself. 1938 came after a lesser-known 1936 one, was followed by a 1944 one, then two in 1954, two more in 1960/61, another pair in 1991... plus a couple dozen near misses.

We're 28 years since our last direct-hit hurricane. This fact, and the list of New England storms, show two things.

One: We don't get frequent hurricanes.

Two: We're due for one.


This week's entertainment in Harwich and Yarmouth were a small example of what a hurricane of similar intensity could do if she made landfall on the Sandy Spit.

Keep in mind that tornadoes produce isolated damage and only hang around for a few minutes. Tornadoes are a mile wide at best, while peak hurricane winds may stretch 50 miles from the center.

While a hurricane won't stay for 6 tides like a Nor'easter can, they do have a wide time window when compared to a tornado.

The Harwich tornado was 250 yards wide and stayed down for 2 miles and change. Yarmouth was the same width, but it stayed down for 5 miles. They combined to last 15 minutes. Damages were more widespread, but still flowed along the narrow path of the storms.


A strong Category 2 hurricane coming ashore in Yarmouth would do damage similar to that seen this week. However, the damage would be regional.

The whole Cape may suffer damage similar to what Harwich got. You could probably throw in the South Coast and South Shore too.

Power was out for 4 days in Harwich, and that is with Eversource flooding workers into the area. I run a Bourne hotel, we were full of Eversource crews, and we turned away a dozen other crews. Fire departments, the National Guard and even prison labor helped get the power back on as quickly as they did.

Imagine if all of Cape Cod was like Harwich? Exponential damage? Eversource and company wouldn't be able to focus on one line of damage, in one or two towns, like they did this time. Crews would be spread out from Provincetown to Fall River to Hull. Power could be off for months.

Harwich lost 150 trees, all along the tornadoes' paths. A Cape-wide version of that may take down 20000 trees, dumping them across roads, through houses and onto power lines... from Onset to Orleans.

Let's not forget that even minor hurricanes do catastrophic damage along the coast, via wave action. Our tornados were ashore and inland for most of their lives.

As bad as these tornadoes were... we got off easy. Our next natural disaster, for which we are far overdue, won't be so isolated.


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