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A nerdy scientist’s assessment of risk – Tornadoes vs. Earthquakes

Tornado Risk map - Dakotas

Tornado risk map from the National Weather Service for July 17th, 2015. Sioux Falls was squarely within the 2% zone, meaning there was a 2% chance of a tornado being seen somewhere within 25 miles of your location. Somehow…we all survived.

While at a conference for work in Portland last week, my colleague and I had a nice supper with two USGS colleagues who work in Menlo Park, California and Seattle, Washington, respectively.  We had relayed the news that the night before, there was storm damage in the area, with straight line winds and tornadoes both causing damage.  The West Coast colleagues…oh…let’s just call them “Ben” and “Tamara”…were flabbergasted that we’d want to live in an area so prone to devastating storms.

Tonight, the National Weather Service put out the map I’m showing here, noting that parts of South Dakota had either a 5% or 2% chance of a tornado hitting somewhere within 25 miles of your location. Let’s do the math!  What are the odds of a tornado hitting YOUR exact location on a night like this, when tornadoes were indeed spotted?

An area with a radius of 25 miles is over 54 billion square feet of territory. What are the odds of a tornado hitting your bit of territory, with a 2% chance of one being seen somewhere in this area? The average tornado path is 4 miles, or 21,120 feet. Average width is 500 feet. The average damage path is 10.5 million square feet. Even if you’re in the highest probability area, 5% chance of one being seen relatively near, the chances of one hitting YOUR chunk of territory…0.0010%. For the 2% chance of a tornado near you, the odds are 0.0004% it will strike your exact location.

Without Warning - Oregon Cascadia earthquake Comic

An actual comic-like booklet put out by the Oregon Office of Emergency Management. Yes, West Coasters…you’re in imminent danger of being swallowed whole by a massive earthquake. Tornadoes in the Plains? They’re nothing in comparison.

Just a guess…but we probably have chances similar to this only like 4-5 times a year. If you just use the same strike probability assumptions, you thus only have, likely at absolute most, a 0.0050% chance of a tornado hitting your location in a given year.

That’s an average of about one hit on your exact location every 20,000 years. Most tornadoes are weak F0 or F1, so even a hit might not be that bad.

Now, let’s reconsider the situation for my colleagues living in California and Seattle.  This week the New Yorker ran a story about the upcoming massive Cascadia subduction zone earthquake that could hit, The story said on average, something similar to the massive 1700 earthquake thought to have hit the area occurs about once every 250 years.

Put it all together, and Seattle is 80X as likely to get walloped with a 9.0 earthquake as Sioux Falls is to get a direct hit from a tornado, and even a direct tornado hit in Sioux Falls is likely to be far, far, less damaging than any earthquake.

You are welcome, West Coast storm-haters.  I hope I have reassured you that is once again safe to visit us in stormy Sioux Falls.  🙂

F***ing, Fat, Fake Nature Lovin’ Campers – FFFNLCs

Vegetation removal at Big Sioux Rec Area - 2013 to 2015

Big Sioux Rec Area campground – 2 years ago, and today. All shrubs and trees anywhere close to the road removed, any remaining trees trimmed way up. Can’t have any scratches on those $125,000 RVs!!!

We live across the street from the Big Sioux Recreation Area, a state park here in South Dakota.  It’s a riparian area along the Big Sioux River, with many very large cottonwoods and burr oaks, among other trees.  We’ve lived in Brandon for over 20 years now, and I’ve always enjoyed the park, including the birds found within.  That enjoyment is becoming less and less as time goes by.

There’s a definite pecking order in terms of what passes for “recreation” in South Dakota.  Birds and birding, and wildlife in general, seems to be very far down that list.  “Parks and Rec” often seems to mean accommodating a few select recreational uses of public land.  Hunting definitely tops the list.  What else would you think when you get to your favorite  South Dakota State Park, and are immediately greeted with a sign that says “Warning – Hunting Season in Progress”?  Nothing says rest and relaxation more than walking a beautiful path, looking for birds, all the time with a wary eye for any trigger happy hunter that may be targeting something in your general vicinity.

Accommodating campers seems to be the second highest priority.  The Big Sioux Recreation Area has always had camping spots, but until recently, they’d been wonderfully vegetated.  There are two loops with camping spots, loops that USED to be lined with cedar trees and other vegetation.  They were wonderful for birding. The deciduous trees and shrubs around the camping sites themselves were sometimes spectacular for warblers and other migrants in the spring.  The thick cover offered by the cedars and surrounding bushes always attracted birds.  A few years ago on a beautiful November day, as my son and I walked through the park, we were surprised by 15 or more Long-eared Owls that were roosting in the evergreens.  They were incredibly tame, allowing close approach.  People came from all around the area to see this unique circumstance, a group of tame, easily seen Long-eared owls that had chosen the Big Sioux Rec Area camping loops as their winter roosting spot.

Long-eared Owl - Asio otus

From 2007, a Long-eared Owl perched in trees in the campground at the Big Sioux Recreation Area. Those trees and any other vegetation in the vicinity are GONE, largely to make way for today’s generation of Fat Fake Nature Lovin’ Campers.

Last summer, the park began removing trees and shrubs.  Ostensibly, part of the reason was due to what’s become an all out war on Eastern Red Cedar by parks in the state.  However, one of the directly stated reasons for the move?  All the increasingly large campers that use the Big Sioux Rec Area were having a difficult time backing into some of the camping spots.  Those cedar trees that held all the Long-eared Owls?  They are ALL gone.  All the bushes and other vegetation that used to line the roads of the camping loops?  Gone.  What was once a wonderful habitat for birds is now a habitat for…FFNLCs.

What is a FFNLC, you ask? My very blunt term for “Fat Fake Nature Lovin’ Campers”.  Frankly, I usually put another “F” in front of the term, and you can imagine what that stands for.  DEFINITE “Fake nature lovers”, given what passes for “camping” at the Big Sioux Recreation Area.  Last night, I was walking through the park and passed a MASSIVE RV that has been parked in the same spot all week. Despite being there for several days, I had yet to actually see someone OUTSIDE, until last night.  Last night, there was a definite FFNLC, “roughing it” in the park.  This FFNLC was massive on a grand scale, just as was her RV!  And just as massive was the huge flatscreen TV she watching in the “wild” of the park.  The RV had a panel on the outside that opened to reveal this massive flatscreen TV. This FFNLC was sitting in a lawn chair with a huge bowl of chips(?), munching away with the volume turned ALL the way up so the rest of the park could also enjoy her viewing of American Idol.

NOTHING says “Nature” more than sitting in a lawn chair, with your satellite TV hooked up, watching a giant screen and speakers belting out American Idol.  And now you see why I usually add another “F” in front of FFNLC.  Even if there WERE a bird in the general vicinity of the VERY fat FFNLC, there’s no way I could have heard it over her TV.

Fox Sparrow photo - Big Sioux Rec Area

Fox Sparrow, taken in the campground loop at Big Sioux Rec Area. Alas, this spruce tree, like EVERY spruce and cedar tree in that loop, is now gone.

I don’t want to be mean about the “fat” part of FFNLC, but…c’mon, it fits SO well for FFNLCs.  This weekend, on a GORGEOUS afternoon, I took a walk through the park with my pups.  There’s a nice, long, paved bike/walking trail through the park that we like to take the pups on.  Beautiful day…many campers at the park…gorgeous trail…and for the 1 1/2 mile walk, do you know how many people I came across on the trail?  ONE.  ONE!!!  But yet you got back to the campground area itself, and there were certainly plenty of FAT FFNLC’s “roughing” it.  “Roughing it” nowadays evidently means never moving more than 15 feet from the vicinity of your massive, air conditioned, satellite TV equipped, more-comfortable-than-most-peoples-houses, 40-foot RV.  TAKE A FREAKIN’ WALK, FFNLCs.  TRY TURNING OFF THE TV and actually enjoying the park itself.

There’s obviously no going back.  My very birdy camping loops are no more, and it’s not going to change.  EVERY change the State Parks make around here end up REMOVING habitat, and putting in MORE camping stalls.  I guess I should enjoy what habitat remains in the Big Sioux Recreation Area, because its inevitable that any bird habitat presently found there is only going to be reduced even further as time goes by.

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