winter tornadoes?

[ddowney]

This is a question I've been wanting to ask someone. Has there been reports of tornados that have happened while it is snowing? And if not that , has anyone seen a tornado while a lot of snow is on the ground causing the tornado to become white with snow?




Damien

 

[Andy Wehrle]

The closest thing I've heard of is on days like March 20, 2006; when snow was falling just a short distance from the tornadic storms and the tornadic storms themselves were producing not hail, but something like icy "slushballs". The chasers who were there would be able to elaborate better. I've also read about an instance in winter 1975 when a deadly tornado in Altus, Oklahoma was closely associated with a snow-producing winter storm. However, I couldn't tell you if the tornado actually passed over snow-covered ground. I imagine the pockets of cold air near the ground associated with areas of snow cover would not be the greatest thing for maintaining the tornado's updraft and circulation.

 

[Jeff Miller]

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

And a format question...should this not be in the weather forum?

 

[ddowney]

Alright that snowspout is nice. Id love to see what would have happened if it flowed over some empty land. Im new at this , is there a way to move this thread to the weather forum?

 

[afischer]

I've also read about an instance in winter 1975 when a deadly tornado in Altus, Oklahoma was closely associated with a snow-producing winter storm.

This was an "interesting" case to say the least. Here are a couple of links on this event from Jonathan Finch's page.

http://bangladeshtornadoes.org/UScases/022275/022275pth.gif
http://bangladeshtornadoes.org/UScases/022275/02227504zsf.gif

As for the original question, it's next to impossible to attain deep surface-based instability when your temperature profiles support snow. The rare cases you can achieve such instability is usually a postfrontal airmass within deep westerly flow, which typically doesn't support mesocyclonic tornadoes. However, there are a good handful of vigorous closed-lows in the cool season which have supported cold core tornadic mini-supercells within 100 miles of a heavy snow band.

 

[Brian Stertz]

Had a close call with snow and tornado event overlapping on April 10, 2005 west of Hays with tornado warnings and winter storm watches in effect for same county. That was pretty zany.

 

[Dan Robinson]

I think the most likely scenario for this to occur is if a normal warm-sector tornado were to pass over a surviving snowpack produced from a previous winter storm. The snowpack would only need to be deep enough to survive extended melting (several days) from being in the warm air prior to the tornado event, and it shouldn't have an adverse cooling affect on the boundary layer if return flow was strong enough. This has 'almost' happened a few times that I am aware of, but the snowpack did not survive the warm return flow and entirely melted long before the severe weather event.

For example, picture if today a strong trough suddenly dug into the Plains and started vigorous return flow of 60F-65F into southeast Kansas. Providing a narrow and sharp instability axis and extreme shear - as long as the snowpack survived the brief warmup, any tornadoes in SE Kansas and Missouri would be white with snow.

I've never seen the snowspout example - if I'm not mistaken though, the snowspout is a rotating column of fog on the lake rather than a column filled with snow?

 

[Jason Doss]

Winter weather advisory/Tornado Warning

Just a few weeks ago, most of central Texas was under a Winter Weather Advisory with a Tornado Warning in several counties. We were out chasing a few cells in the Waco area and had to make sure we headed south before the sleet arrived. Pretty cool when two extreams are happening at the same time.

 

[Greg Stumpf]

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

Never knew there was a Wiki entry for this term until now. It is very rarely used.

It does say only 6 have been known to have been photographed. I wonder if my photo is one of the 6, although I've never really publicized it. Mine was clearly a waterspout (not a steam column) occuring under the band about a mile offshore the SUNY Oswego campus while light snow was falling during a lake-effect event, sometime during the winter of 1982-1983. It lasted about 3-5 minutes and dissipated offshore. I'll have to digitally scan it someday.

Robert Sykes, the late renouned lake effect expert of Oswego, once reported during a snow squall white out a brief "roaring" sound in his back yard. When the snow subsided hours later, he found tree damage in the tree row at the back end of his property. It was then when he coined the term "snowspout". He lived about 1/4 mile from the lake shore, and this was clearly a lake-effect induced tornado that moved onshore during a heavy snow event.

 

[ddowney]

Thats very awesome . If a tornado as we call it was to form during a major ice storm or snow storm, would you believe the damage would be higher at lets say 130 mph winds ?

 

[Scott Lincoln]

Blizzard Warning with Mesocyclone

I dont remember the date but i have archived Level2 NEXRAD data from a case where there was a very small area of intense precipitation that was falling as snow, where ground reports were indicating zero visibility from the intense but brief snow squall. The NWS out of Des Moines issues a blizzard warning for this small system. On radar it was definitely rotating, visible on both reflectivity and velocity. If it was not for the fact it was snowing... i would have been seriously quesitoning why a tornado warning was not issued as it looked to me like a good example of a bow echo induced tornado case with mesocyclones forming and dissipating in front of the intense precipitation. I think this small squall may have been associated with a vort max, but i didn't end up having the time to go back and look into the case like i originally wanted to. I always wondered if it possibly could have been strong enough to produce a tornado, but it would be hard to know since it was in zero visibility....