wind seminar   Lee Frelich
  Feb 04, 2007 18:54 PST 


I just got back from the Enhanced Fujita Scale/Wind Damage seminar
sponsored by Ernie Ostuno's office of the National Weather Service. I got
an Enhanced Fujita Scale certificate, so now I can go out and examine
tornado damage and make an official pronouncement as to the level on the
new EF scale that has been in use since Feb. 1.

The seminar was held in Mount Pleasant, MI. The place was pleasant enough,
but it was also as flat as a pancake for miles in every direction, so I am
not sure where the 'Mount' in the name came from.

My lecture was on wind damage in trees, and unfortunately, my data
indicated that susceptibility to blow down is a function of successional
status of tree species (late successional species less susceptible),
whereas the EF scale people wanted it to be hardwoods versus softwoods.
Actually, trees arrive at their level of susceptibility by various
combinations of wood and growth form traits so that wood strength alone is
not a good predictor. For example, the species with the weakest wood in
northern MN (white cedar) is also the least susceptible species.

The drive home from Mount Pleasant was a real wind experience. I used twice
the normal amount of gas driving several hundred miles against winds up to
50 mph. I gave Lake Michigan a 70 mile wide berth as I left Michigan, and
experienced only light lake effect snow that far inland. Then in Indiana, a
heavy ground blizzard for about 50 miles with millions of tons of fluffy
snow in horizontal motion perpendicular to the highway. It was impressive
for Indiana and the blizzard would have been worthy of western MN. Then an
extremely heavy lake effect snow band with visibility of about 50 feet,
which fortunately was only about 10 miles wide. Then more ground blizzard,
then a dust storm in Chicago, and a return to Minneapolis and -5 degrees at
mid day, with wind chill temperatures of -25 to -45. The last week has been
a welcome taste of winter, although nothing like it was in years
past. Fortunately I have logged 1000s of miles of travel in ground
blizzards and extreme cold, so it wasn't much of a problem.

RE: wind seminar   Ernie Ostuno
  Feb 05, 2007 04:31 PST 


Thanks again for coming out and helping to get us meteorologists up to
speed on the wind tolerance of various tree species. I only wish you had
been consulted when the EF scale was being devised.

Glad to hear you avoided the very worst of the lake effect snow on your
return trip. Central Michigan in February is not the most "pleasant"
destination, even for a seasoned arctic traveller like you. Here in
Grand Rapids we had true blizzard and white out conditions while setting
a daily snowfall record of 11 inches on Saturday, with air temperatures
around 5F and winds gusting over 40 mph. The highways were closed down
for several hours due to multiple car pile ups. It was probably the
worst lake effect blizzard here in more than two decades. It finally
cleared out Sunday night, but that allowed temperatures to plummet to
about 10 below...which I believe is the temperature that Minnesotans
close their bathroom windows at.