Tornado or Landspout? (year, occur, country, north)
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So, a while back it was fairly big news when Southern California was hit by a tornado last year (although California sees a dozer or so a year). Out of curiosity, based on the video below, can somebody from the Midwest (or anybody familiar with mesocyclones or meteorology in general) tell me if this was actually a tornado produced from a supercell, or merely a landspout (which I guess, depending on wind velocity, could still be considered a tornado)?
Also, if it a supercell, how can you tell?
I'm somewhat fascinated by extreme scientific phenomenon, so it's somewhat exciting (thank god nobody got hurt) that we actually had a tornado here in California (I've seen funnel clouds a few times, but never an actual twister). What are the identifying features of a tornado vs. a landspout?
All land spouts are tornadoes. However, land spouts are usually non-convective. Judging on the videos, these were convective and full fledged tornadoes.
Generally speaking (at least in this country) a landspout is considered a minor weak tornado which occurs only due to very low level shear in a cumulus or cumulonimbus cloud near a convergence zone, or a "misocyclone" which may be embedded in a squall line.
Whereas a "proper" tornado is formed from a severe, self perpetuating thunderstorm with a deep mesocyclone, in other words, a supercell.
The best way to tell if it was a supercell or not is to view a tephigram of the troposhere and hodograph at the time when the storms occured and in that location to see if upper level directional and speed shear & instability was conducive to supercell activity. You would need to know a bit about how to read those graphs.
If you have pictures of the event then there are certain visual features to be observed if it was a supercell, such as the dry slot (rain free base) associated with the rear flank downdraft, wall cloud with rotation denoting the presence of the mesocyclone, flanking line, etc...
These would be observed best from the south east if the storm was moving south west to north east and at the rear flank of the storm.
These are just general features and not all such storms have such obvious clues.
Thanks for the replies! Unfortunately, these Youtube videos are all I can dig up on the tornadoes in question. How common are supercells? Do they only occur in the Midwest? I've seen some very angry looking thunderheads around here, and even a funnel cloud, but never a proper tornado. How can storm chasers tell when tornadoes are likely?
I'm of the understanding that Tornadoes are most common in summer, when warm moist air meets warm dry air (at a dry line). When looking for possible tornadic activity, is it most likely when a squall line passes over (which almost never happens here in the Sierra)?
Thanks for the replies! Unfortunately, these Youtube videos are all I can dig up on the tornadoes in question. How common are supercells? Do they only occur in the Midwest? I've seen some very angry looking thunderheads around here, and even a funnel cloud, but never a proper tornado. How can storm chasers tell when tornadoes are likely?
I'm of the understanding that Tornadoes are most common in summer, when warm moist air meets warm dry air (at a dry line). When looking for possible tornadic activity, is it most likely when a squall line passes over (which almost never happens here in the Sierra)?
I've lived in the west for a time (California and Oregon), and I noticed that this region gets mostly landspouts, while other regions tend to get true tornadoes. I think this is because the west doesn't get invaded by contrasting air masses, very often at all. The midwest and great plains regions, are quite often invaded by strongly contrasting air masses, which contributes to strong tornadic development there.
I've lived in the west for a time (California and Oregon), and I noticed that this region gets mostly landspouts, while other regions tend to get true tornadoes. I think this is because the west doesn't get invaded by contrasting air masses, very often at all. The midwest and great plains regions, are quite often invaded by strongly contrasting air masses, which contributes to strong tornadic development there.
Oregon just got hit with a EF2 tornado in December 2010. This page has the biggest photo I could find of a tree blown over.
Didn't know about the new enhanced Fujita scale until I followed the link the page provided to further reading.
WOW!! Looks like that was a fairly strong tornado, based on the damage in the photo. Well I guess that Oregon CAN get strong tornadoes, on rare ocassions.
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