| Yesterday's
storms: MN Sept 21, 2005 |
Lee
Frelich |
| Sep
22, 2005 20:56 PDT |
ENTS:
An unusual supercell downburst and tornado, or possibly two
tornados,
narrowly missed my neighborhood last night (we experienced minor
winds of
60-65 mph for 10 minutes). The north side of town was not so
lucky, as the
F-2 tornado (winds 112-157 mph) blew the roofs off several
hundred houses
along a two-mile path. A much larger downburst covered about 50
square
miles with winds that I would guess were around 90 mph. The odd
thing is
that the tornado was embedded right in the middle of the
downburst. Usually
a storm switches back and forth from tornado to downburst, but
this one had
both at once.
The technology for real time reporting of storms on TV was
amazing. Paul
Douglas on Channel 4 in Minneapolis has developed software that
turns radar
data into 3-D visual images (I believe he sells this software to
stations
all across the country). We had minute by minute estimates of
wind shear
inside the downburst, which peaked at 92 mph, and also images of
rotation
at different levels within the supercell, which was 55,000 feet
high. When
rotation is stacked at several levels, then a tornado can be
predicted
whether it is visible at that time or not. Rain was so heavy
that the
tornado(s) could not be seen except on radar, and the TV
broadcast telling
people in each neighborhood when to go in the basement was
critical for
keeping the fatalities to just one.
The city of Brooklyn Park lost 5000 trees, and reports of
similar numbers
are coming in from throughout the northern suburbs of
Minneapolis, which
have no power and impassable streets. Many friends who work in
my
department at the university live in the affected area and had
cars and
roofs destroyed by falling silver maple trees. They spent the
day on their
cell phones talking to insurance companies. My advice is to
plant bur oak
and have at least a century or two before the tree will fall on
your house.
I haven't checked the three old growth forests in the northern
and western
suburbs yet--Wood-Rill, Wolsfeld Woods and Taylor's Woods, but
based on the
location of damage reports, I am optimistic that they are still
standing.
At least now it is fall (both temperature and on the calendar),
since the
front that caused the storms pushed out the 70 degree dewpoints
we had
yesterday and replaced it with Canadian air from the boreal
forest.
Lee |
| RE:
Yesterday's storms |
Ernie
Ostuno |
| Sep
22, 2005 21:53 PDT |
Lee,
Here's a web page with some storm details:
http://www.crh.noaa.gov/mpx/2005Sep21Storm.html
Seems like Minnesota and Wisconsin get all the severe weather
"fun"
lately. The same front came through here today and all we got
was a few
hailstones. We did get close to an inch of rain, however which
hopefully
means the summer-long drought is winding down. Bring on the
boreal air!
Ernie
|
| RE:
Yesterday's storms |
le-@goldengate.net |
| Sep
23, 2005 06:22 PDT |
| Ernie:
Thanks for the website reference. There are several slide shows
of the
storm damage in the Minneapolis area on the channel 4 website
www.wcco.com
(scroll down to 'Andover storm damage' and click on the slide
show).
Several other slide shows with damage in other areas will pop up
as well,
including storms Monday night that apparently levelled houses
and didn't
even get mentioned on the news.
We had a lot of large hail as well. I'll bet there be 100,000
hail damage
cars for sale cheap in the near future. These cars are
mechanically just
fine but they don't look good with all the dents.
You are right about the severe weather in MN and WI. MN has had
62
tornadoes this year, well above the average of 30. WI set a
record for the
most tornados ever recorded in one day during August.
Our drought has ended, since we have had almost 8 inches of rain
in the
last two weeks. This period of late season rain has led to some
curious
impacts on trees. Some flowering crabapples are starting to
bloom in
response to the rain. I wonder if they will be able to get ready
for
winter in time, and if they will bloom again next spring?
Lee
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