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by mnwxchaser from Buffalo MN

Last Post 17 days, 11 hours Ago


July 11th Becker county MN tornado
Jul 14, 2008 | 11:58 PM
Category: Weather
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Obviously the big story on the Minnesota weather scene was the EF3 tornado in Willmar, but  there was also a handfull of tornadoes in the northwestern part of the state near Waubun, Fosston, and Frazee, MN.  I chased the cell from Rothsay,MN to near Wolf Lake, MN where the supercell did put down a brief, weak tornado near Frazee (the picture below):

July 11 2008 Frazee MN tornado

Many more pictures from the chase can be seen HERE

What a beautiful ending to a spectacular chase day.




Bill


4 Comments |  Add a Comment

Member Comments Total Comments: 4
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CherokeeKid read my blog view my photos
Aug 24, 2008 | 12:32 PM

You know getting near a tornado is a dangerous thing to do, especially if you do not have place to take cover in.

If you are ever in a situation where there is a tornado watch or warning, you can estimate its general direction for where you are from the direction of the wind.

In most situations, the wind blows towards where a funnel cloud is. The closer you get to a funnel cloud that is at or near ground level, the stronger the winds become until they have a damaging effect.

Most tornadoes are contained within what is called a "wall cloud", which is a front line of a thunder cell. Wall clouds usually are lower to the ground level than a surrounding cloud type, because they are the border of temperature and barometric variances, that cause an uplifting of warmer air that is carried aloft in to the atmosphere while cooler air goes below, and wedges itself across an area it is moving.

Wall clouds consist of cumulus, stratus, and cumulonimbous clouds, in a very small area, which creates an extreme pressure variance that causes wind speeds to increase until those temperatures and pressures are equalized.

Tornado classifications are based on wind speed and damage that they are able to cause. It is called the Fujita Scale, I believe. They range from a category 1 to category 5, or F1 to F5.

You must have an updated classification system or with the E identifier at the beginning, of the one you took pictures with. Is the "E" a designator for something else not I.D. ed on the Fujita scale?

CherokeeKid
mnwxchaser read my blog
Aug 28, 2008 | 9:38 PM

CherokeeKid: thanks for your comment. I have over 130 tornadoes in my career and feel quite confident of my ability to safely observe these from a comfortable distance.

The EF scale was put into effect by the NWS and SPC in February of 2007. Only Canada is still using the only Fujita scale. The alteration was to allow for a more realistic assessment of the DOD (degree of damage) due to a lesser quality of construction in many of the newer structures. Basically, it takes less wind to do more damage now than it did 20 years ago. Sad, but true. I suggest reading the information provided in this link:

http://www.spc.noaa.gov/efscale/ef-scale.html

Wall clouds DO NOT occur on the leading edge of a thunderstorm. Wall clouds are located at the interface of the updraft and downdraft. A pressure variance has nothing to do with it. The wall cloud is caused by warm moist air being pulled in to fill the void left by the explosive updraft above it. The rapid cooling of the air as it is pulled into the updraft causes the moisture to condense into cloud matter. Wall clouds are rather common during the inflow phase of a thunderstorms life cycle but a wall cloud with rotation (much less strong rotation) is not very common.

Your description above is more that of a shelf cloud (arcus) which is the result of rain cooled air shooting out under a forward flank linear updraft where the moist air is forced upward by the forward movement of the cell. Any true wall cloud (which follows the precip core and does not lead it) which has cool air undercutting it is not capable of
mnwxchaser read my blog
Aug 28, 2008 | 9:39 PM

tornadogenesis.

A basic source of information regarding the elements and type of cell necessary for tornadogenesis can be found here:

http://en.wikipedia.org/wiki/Tornadogenesis

Again, thanks for the comment and feel free to ask more questions.

Bill D
CherokeeKid read my blog view my photos
Aug 30, 2008 | 1:04 AM

Thanks Bill, I appreciate you clearing that up for me. I have been through a few tornadoes myself, and it really has an effect on many things when they occur, but have never suffered any structural damages, or injures myself.

How do you think flooding and tornadoes could be related when water spouts are formed?

CherokeeKid
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mnwxchaser

Part time professional storm chaser with 25 years of experience and full time cubicell dweller the rest of the year. I have done work for Fox9 as a independent video stringer/chaser for 3 years now and have had a blast working with the weather crew at KMSP. A bad storm is always better than a good day in the office! So you like storms and severe weather in Minnesota? Check out the website at www.mnwxchaser.com for a lot more.

Member Since: 7/14/2008


 

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