I’ve received an email (see below) from someone who lives about 2 miles away with a question about a possible tornado in the area. As tornados aren’t common in this area I’ve nevr taken much notice of the conditions that cause them, so I can’t definitively answer the question, but it does sound like it has some of the aspects that a tornado might have. I thought the assembled experts here might be able to offer some suggestions on whether it was a tornado or something else.
Last night in Layton we beleive there was a small tornado in Layton. Is there anyway we can find out if this is
the case? At around 9.30 pm last night we heard a loud growling noise going over the house. My husband looked out
the van was rocking and the garden gate was going mad. My father who lives round the corner at around the same
time tried to go outside and the suction from the wind prevented him from opening the door. He looked out the
rain was going down the street horizontally with debris etc. His canoe which is very heavy and secured down was
found snapped in 2 down the street and ridge tiles indented in walls.Neighbours cars have been dented from roof
tiles. A house on other side the cemetary had all roof tiles blown off. After talknig to people it seems a small
path of destructon has been formed. Touchdown near foxdale ave across layton cemetary and into Annesley Ave then
back up.Spoke to other friends and family and they have heard nothing and experienced nothing
. Apparantly it was completely calm. Could you give any more information as to what it was as there is no way
wind could have done this kind of damage. The noise was like a train going over the house the fire was shaking in
the fire place etc, this is very unusual even for high winds! Could it have been the tail end of the one reported
in Wales? Please reply asap
I doubt it’s related to the tornado reported in Wales…that was in South Wales, about 150-200 miles away. I’m also going to try to find out exactly when it happened. I think from the timing of the message it must have been at 21:30 on 27th December. If that’s correct then it corresponds to the point on the graph below where the pressure has dropped to it’s minimum, the wind changes fairly quickly from southerly to north-westerly and there’s a fairly heavy squally of rain.
The short duration and complicated nature of tornadoes make them nearly impossible forecast. Meteorologists don't really know the specifics of how they form, but they do know what atmospheric conditions were present during past tornadoes. They use this knowledge to try and identify tornado threats before they happen. The earlier they realize that a tornado is going to strike, the earlier they can notify residents of the areas which will be hit. The more warning people have, the fewer people will be killed.
To know the current atmosphere conditions, meteorologists send up weather balloons every twelve hours to take soundings of the upper atmosphere. The equipment on the balloons measure conditions such as the atmospheric stability, temperature, and relative humidity. Two conditions tornadoes need to form are high instability and a high dew point. When these conditions exist, they issue a tornado watch.
A new type of weather radar can greatly improve the time between tornado detection and tornado touchdown. Conventional radar could only be used to detect a tornado after it had formed, usually by seeing a shape such as a hook echo on the radar return. The echo doesn’t appear with every tornado, so forecastor can’t rely on just that information. They also need observations from tornado spotters in order to issure a tornado warning.
Unfortunately I don’t know of anything that covers this area.
Also I’ve just checked the map of the roads. I don’t know which direction the path took, but it was in the segment W->E and SW->NE which fits with the wind direction. The only identified damage is within quarter of a mile of each other, so it probably wasn’t a big tornado (the few that we ever get are fairly small and localised).
That map looks interesting. The winds were from the south hitting a cold front coming from the north west. No warm front in the area at the time and (according to my recently semi-installed lightning detector) no thunderstorms in the area at the time, although you the conditions were stormy.
I don’t live in tornado c but when we have had them I seem to remember hearing that if the fallen tree pattern had a twisted pattern thatwas a sign of a tornado, as compared to a pattern where the trees fall in the same direction.
It could be related Chris - there was a severe squall line passing through that evening in a SE direction - had it here in Bristol - even Cornwall had it - caused gusty winds and severe hail and power outages so if the conditions were right for a tornado along that squall then that is probably what it was.
Sorry, bad wording on my part. What I meant was that it was unlikely to be the same tornado. Looking at the way the cold fronts are angled it does seem likely that they may have caused the same effect in both locations.
I went for a drive round the area before lunch and from what I could see there is a fairly well defined narrow path of damage. I’ve marked the map with the locations where I saw damage (ridge tiles blown off, tiles lifted/removed) with blue blobs. The initial part of the path (assuming a west->east path) seems fairly straightforward. The end of the path seems too wide (it’s 150 yards or so between the damaged roofs), so perhaps it curled back on itself at some point. I’m assuming all the damage I saw was related to this event. The damage was fairly localised, with houses either side of the path looking undamaged.
If this was a tornado then it was nothing like one of the big tornados that other areas of the world suffer, but there are some people around with expensive repair bills!
there really is not “written in stone” criteria for determining a tornado here in the US.
Who surveys tornado damage? What's the criteria for the National Weather Service to do a survey? This varies from place to place; and there is no rigid criteria. The responsibility for damage survey decisions at each NWS office usually falls on the Warning-Coordination Meteorologist (WCM) and/or the Meteorologist in Charge (MIC). Budget constraints keep every tornado path from having a direct ground survey by NWS personnel; so spotter, chaser and news accounts may be used to rate relatively weak, remote or brief tornadoes. Killer tornadoes, those striking densely populated areas, or those generating reports of exceptional damage are given highest priority for ground surveys. Most ground surveys involve the WCM and/or forecasters not having shift responsibility the day of the survey. For outbreaks and unusually destructive events -- usually only a few times a year -- the NWS may support involvement by highly experienced damage survey experts and wind engineers from elsewhere in the country. Aerial surveys are expensive and usually reserved for tornado events with multiple casualties and/or massive degrees of damage. Sometimes, local NWS offices may have a cooperative agreement with local media or police to use their helicopters during surveys.
http://www.spc.noaa.gov/faq/tornado/#Damage
as weatherbee said, there should be some sort of twisting debris pattern. IMHO, using that to determine if a tornado happened will be easier than seeing if the conditions were "correct".
We have them around here a bit due to the number of thunderstorms.
We have only had one Tornado near here since I moved here 12+ years ago. that was behind us across the way in an open field. I do remember that due to the hail and the noise. Took out a small barn but that was about it.
Microbursts can be very powerful though. They have been known to level a line of power polls several hunderd at a time. Pretty cool to see unless you live then since you don’t have power then. They can knock down houses etc… too.
You can have tornados about anywhere, although out my way they happen more often. I think I saw something about one in India a while back. Anyway, they suck. #-o
here in NZ there is always hot debate on wether damage was from a cloud burst or a small tornado
generaly though if people see lots of debri blowing up in the sky, then its a tornado
now, one person reports he could not open his front door becuase of the pressure of the wind
if it was a tornado passing over, the pressure actualy lower outside, which helps the house explode (along with the very strong winds!)
opening leeward windows could in theory stop the house from exploding outwards in a tornado (yeah right who is going to be able to do that)
A. It’s a myth that open windows equalize pressure and minimize damage when a tornado strikes. Opening windows allows damaging winds to enter the structure. Leave the windows alone and immediately go to a safe place.
Q. Doesn’t the low pressure associated with a tornado cause buildings to explode?
A. Violent winds and flying debris slam into buildings and cause most structural damage.
A. It's a myth that open windows equalize pressure and minimize damage when a tornado strikes. Opening windows allows damaging winds to enter the structure. Leave the windows alone and immediately go to a safe place.
which is why said to open it on the leeward side
but becuase the winds will most likely come from all compass angles in the end, then that will not work
Q. Doesn’t the low pressure associated with a tornado cause buildings to explode?
A. Violent winds and flying debris slam into buildings and cause most structural damage.
Having lived in Texas and the Carolinas and experienced many tornado warnings, funnel clouds, wall clouds, squall lines, down bursts and heat bursts, I can say that it is very difficult to say what causes the damage if no one saw a tornado, especially for such relatively minor damage. Here is my very insignificant opinion:
The 2 cold fronts so close together is unusual. Tornadoes in the central USA most often occur where a dry line (a humidity front) is followed by a cold front, and proceeded by a very warm moist southerly flow. It is possible the 2 fronts depicted on the map could represent a similar situation. The winds are from the southeast over eastern england, which would be warm and moist, they are westerly between the fronts, which could imply some drier air, and the are northwesterly behind the second front.
The is clearly an unusual shift in the isobars in the first map, off the coast of Cornwall. Wind would shift from west to northeast to northwest very quickly, so there is potential for rotation within clouds.
Was the squall line along the first front or second front?
The strong ridge of high pressure off the to the south and west would resist the front, a situation which often leads to winter tornadoes in the USA.
What was the temperature profile across the 2 fronts? If it was 10C or more, that might be sufficient to support a tornadic storm.
Storms within a squall line which contain hail are common within a line that also produces tornadoes. Were there any reports of thunder?
A sudden squall of wind and heavy rain has caused severe damage to dozens of houses in west Dublin and Co Meath.
The worst affected area was Clonee, where over 100 houses, on the Hansfield, Castaheaney and Hunters Run estates, were damaged.
At least one car was overturned and others had their windows smashed by what local people describe as a mini tornado that swept through the area shortly before 1pp
