Can you have Severe Thundersnow?

[Saul Trabal]

I'm thinking back to that massive superstorm that hit the east coast of the U.S. in 1996 (?) I love to see thundersnow. It's an awesome sight.

In Northern New Jersey, the blizzard dumped more than 5-6 feet of snow. And I saw what to me must have been severe thundersnow. Lightning was almost continuous.

So-I guess it's possible to have a severe thunderstorm that's strictly a snow event, yes?

 

[Tony Laubach]

So-I guess it's possible to have a severe thunderstorm that's strictly a snow event, yes?

Here's my take..

A definition of a thuderstorm; a storm which has thunder (not official, but in agreement with most everyone).

A definition of a severe thunderstorm; thunderstorm producing hail that is dime size, 0.75 inches in diameter or larger, and/or wind gusts to 58 mph or greater, and/or a tornado.

I guess if you have thundersnow which contains a wind gust in excess of 58mph, you could theoretically have a severe thundersnow warning. Unless you have huge gropple (sp?) bigger than .75 that could be construed as hail or an F-2 snownado, I would imagine the only thing to meet severe criteria could be the wind.

This leads to blizzards, though.. but I imagine the convection associated with thunderstorms/snow could separate a blizzard containing high winds and a convective snow event that has high winds.

Just my take...

 

[Aaron Kennedy]

Last winter I am pretty sure there was a severe thunderstorm warning issued for thundersnow cell in central Illinois I believe. I am sure someone has the text. Then again I may be dreaming...

Aaron

 

[David Draun]

I believe there is a post somwhere here that mentions an alleged tornadic mini-supercell that produced some snow in Britain not too long ago

 

[Marko Korosec]

I was in champaign county last winter(in illinois) and a severe thunderstorm warning was issued (I believe in January) for a snow storm. It was a weird setup but basically a strong front was moving through, and the snow storms that were associated with the front were producing 70 mph winds. That does classify as a STW, but it was not due to lightning. I have however seen two thunderstorms in minnesota where lightning was associated with snow storms, so it is possible, but rare.

Rob
www.ciasc.org

 

[Joel Wright]

Funny you posted this, check out the thread I posted on this about a week ago.....


http://www.stormtrack.org/forum/viewtopic.php?t=2685

 

[Scott A. Kampas]

Can 'thundersnow' be severe? The definition used for a thunderstorm and some other things become important.

Conventionally, a thunderstorm is considered to be a cumuliform cloud which has lightning and thunder. However, many of us have experienced and are aware of some intense 'thunderstorms' that have virtually no lightning (most commonly, minisupercells). These storms can most certainly be severe and even produce tornadoes. In Severe Convective Storms, Doswell uses the term "deep moist convection (DMC)" rather than "thunderstorm." This allows for the inclusion of nonthundering convection . I like this way of thinking.

Thundersnow is convective in nature. The heaviest snowfall rates come from convective snowstorms. So the thunder and convection criteria are met in the first case and the convection criterion is met in the latter. As for these meeting the severe criteria, it would be pretty rare, but certainly possible. Severe storms require moisture, instability, lift, and shear; plentiful moisture is very rare in cold air masses though lift and shear (dynamics) certainly aren't. Hail and tornadoes would be much less likely than severe convective winds.

This is what occurred in the Midwest on 11 February 2003. A strong dynamic system moved through the region, spawning thundersnowstorms. These storms exhibited frequent lightning and severe winds. ILX issued some severe thunderstorm warnings for it and took some heat for doing so. They can't really be faulted though as convection, lightning, and severe winds were all present. There was severe magnitude gradient winds associated with this system however, as well. As an aside, snow rollers were also produced over a wide area with this system. http://www.crh.noaa.gov/ilx/events/roller.htm

Scott

 

[B Ozanne]

I believe the snow storm you are talking about is the January 6-7th storm in 1996. Here in Connecticut we got about 30 inches, most in the state in my town. I remember going to bed very late that night watching the news coverage, we were getting 5-6 inches per hour and lots of lightning. I woke up the next morning and my back yard was completely flat, stone walls, patios, boulders all merged into a flat expanse. Northeast winds had drifted the snow so deep our roof continued in an even snow slope to the ground. On a population basis that was the most significant snowstorm in history.

Back to severe. In our minds it was a "severe" storm but technically it would not qualify as a severe storm. Even if a wind gust hit 58mph its unlikely a warning would be issued. It would already be covered in a high wind warning. Hail is out of the question as the processes that lead to hail do not exist in a snowstorm. Grauple is a possibility, but that isn't hail, it's relatively soft and rarely exceeds pea size. Lightning, as intense as it might be, will never qualify a storm as severe.

 

[B Ozanne]

The Salt Lake Valley and nearby Wasatch Mountains frequently get thundersnow and grauple. Under a cold northwest flow above 700mb the relatively warm Great Salt Lake leads to intense convection and lake effect snow bands. Pure Lake Effect events are rare but have single handedly produced over 30 inches in the valley. More common is lake enhancement in a synoptic scale system. Also when you combine lake enhanced snow with 12,000 foot peaks orography comes into play to give parts of the Wasatch over 500 inches of snow a year.

 

[Pat Palmer]

The first and last time I saw thundersnow in person was 1994. 18"-24" of snow fell during the event, and every time I had the driveway shoveled out, the plow filled it back in for me. I considered that rather severe, as well as the invectives I shouted at the plow driver!

I remember shoveling, seeing a flash out of the corner of my eye, and thinking "must be someone taking a picture or an emergency vehicle nearby." Then I heard the thunder. I believe a large grin came to my face as I proclaimed the piousness of excrement.

 

[Jordan Manderfield]

In Mankato,MN I have been in thundersnow twice in my life. The second time was the worst. The winds blew out of the NW at about 55-60 mph for about 10 minutes. The local news said semi's were blown off intersate 90 just south of mankato. They shut down school and I remember trying to walk home in nearly blinding snow. It just pelted your face. We only got about 4 inches of snow but it came in 15 minutes or so.

This was about 2 years ago..........

 

[Dan Robinson]

From last February:

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LINCOLN IL
602 PM CST TUE FEB 11 2003

THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
MARSHALL COUNTY IN CENTRAL ILLINOIS

* UNTIL 645 PM CST

* AT 602 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM...WITH HEAVY SNOW... OVER SPARLAND...OR
ABOUT 6 MILES NORTHWEST OF LACON...MOVING EAST AT 65 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
HENRY
LACON
VARNA
TOLUCA
WENONA

DAMAGING WINDS IN EXCESS OF 60 MPH WILL ACCOMPANY THIS DANGEROUS
STORM. GO TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. ABANDON CARS AND MOBILE HOMES IF YOU ARE IN THE
WARNED AREA.

REPORT SEVERE WEATHER OR ANY STORM DAMAGE TO YOUR LOCAL ESDA...OR THE
NEAREST LAW ENFORCEMENT AGENCY...FOR RELAY TO THE NATIONAL WEATHER
SERVICE. STAY TUNED FOR LATER STATEMENTS.

 

[Tony Laubach]

Now that would be strange to hear... but I figured it would be possible! :shock:

From last February:

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE LINCOLN IL
602 PM CST TUE FEB 11 2003

THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
MARSHALL COUNTY IN CENTRAL ILLINOIS

* UNTIL 645 PM CST

* AT 602 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A SEVERE THUNDERSTORM...WITH HEAVY SNOW... OVER SPARLAND...OR
ABOUT 6 MILES NORTHWEST OF LACON...MOVING EAST AT 65 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
HENRY
LACON
VARNA
TOLUCA
WENONA

DAMAGING WINDS IN EXCESS OF 60 MPH WILL ACCOMPANY THIS DANGEROUS
STORM. GO TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. ABANDON CARS AND MOBILE HOMES IF YOU ARE IN THE
WARNED AREA.

REPORT SEVERE WEATHER OR ANY STORM DAMAGE TO YOUR LOCAL ESDA...OR THE
NEAREST LAW ENFORCEMENT AGENCY...FOR RELAY TO THE NATIONAL WEATHER
SERVICE. STAY TUNED FOR LATER STATEMENTS.

 

[Aaron Kennedy]

I knew I wasn't dreaming.

Aaron

 

[Jim Southard]

Thunder snow is on the checklist of phenomena I decided I must see while in Oklahoma. Haven't had any luck yet, although there was a near miss a couple years ago when we had a convective snowband to our south with some lightning in it.

For those that have experienced thunder snow, what's the experience like? Is the flash of lightning any brighter than in a "liquid" thunderstorm? Is the sound of the thunder different in any way, since I would imagine that snow falling is much quieter than rain falling?

Jim