All Ontario tornadoes

[on_wx]

All confirmed and probable Ontario tornadoes 1792-2009. Touchdown points by census division only. Data from Environment Canada. I built these tables months ago using an excel sheet of lat/lon data by EC.

An F3 tornado was mistakenly put in Algoma District. The tornado was actually in Elgin County. It should be one F3 tornado in Elgin Co, and Algoma District. There was another misplacement in northern Ontario, but I haven't updated the table. Was an F0 tornado.

[snowstormcanuck]

Nice work Mike. I'm still incredulous that 23 tornadoes have touched down within Metro Toronto, even over the course of 200+ years. In fact, looking at that map compared to surrounding Peel and Durham, we seem to be a hot spot? In general though, you can see the effect of the lake shadow keeping the higher numbers inland.

[on_wx]

Nice work Mike. I'm still incredulous that 23 tornadoes have touched down within Metro Toronto, even over the course of 200+ years. In fact, looking at that map compared to surrounding Peel and Durham, we seem to be a hot spot? In general though, you can see the effect of the lake shadow keeping the higher numbers inland.

The is total is obviously much higher for every census division. One of the issues I noticed plotting all the tornadoes is that for pre 1960-data a lot of tornado confirmations revolved around major population centres. Many of those high counts are from cities like Windsor, Sarnia, Chatham, London, Stratford, St. Catharines, Toronto, Barrie, Peterborough, etc. But also, especially for Wellington or Simcoe Counties, most of those tornadoes are weak. Probably lake breeze convergent tornadoes with records around the bigger towns, especially for some reason Fergus.

I'm a little weary of a lot of those GTA tornadoes. Most of those plots were tornadoes spaced apart only a km or two on the same day. I'm not too sure how EC devised this data, but there are a lot of questionable tornado points that were probably the same tornado. A 1946 or so outbreak in the GTA proved this. About 6 F2 tornadoes in Toronto proper.

[snowstormcanuck]

The is total is obviously much higher for every census division. One of the issues I noticed plotting all the tornadoes is that for pre 1960-data a lot of tornado confirmations revolved around major population centres. Many of those high counts are from cities like Windsor, Sarnia, Chatham, London, Stratford, St. Catharines, Toronto, Barrie, Peterborough, etc. But also, especially for Wellington or Simcoe Counties, most of those tornadoes are weak. Probably lake breeze convergent tornadoes with records around the bigger towns, especially for some reason Fergus.

I'm a little weary of a lot of those GTA tornadoes. Most of those plots were tornadoes spaced apart only a km or two on the same day. I'm not too sure how EC devised this data, but there are a lot of questionable tornado points that were probably the same tornado. A 1946 or so outbreak in the GTA proved this. About 6 F2 tornadoes in Toronto proper.

lol, that seems a wee bit unlikely. Could you tell me how many tornadoes have touched down in Toronto proper in recent history, say from 1975 onward? Thanks.

[on_wx]

lol, that seems a wee bit unlikely. Could you tell me how many tornadoes have touched down in Toronto proper in recent history, say from 1975 onward? Thanks.

In progress. Working on 1950-2011.

[on_wx]

SSC haven't forgotten about you. Re-plotting some 500 tornado lat/lon reports takes time and patience. Just hit 1978. Can tell you four tornado touchdowns out of 220 from 1950 to early 1978.

[snowstormcanuck]

SSC haven't forgotten about you. Re-plotting some 500 tornado lat/lon reports takes time and patience. Just hit 1978. Can tell you four tornado touchdowns out of 220 from 1950 to early 1978.

Thanks. Take your time.

[on_wx]

Update on progress...

Over the last few months I've begun to notice:

+ the Environment Canada list I have is missing several vital and sometimes historical tornado events that were confirmed.

+ Other sources have verified tornadoes that are not on this list.

+ Sources confirm many pre-1992 tornadoes were either never confirmed, or were confirmed without an F rating or location reference, and did not make the list.

+ Several event dates may be wrong on my list because they do not coincide with NWS records for SEMI.

+ Locations in Environment Canada records of a couple tornadoes crossing from SEMI into SWON do not match NWS records.

This list is becoming really frustrating.

[andyhb]

That's because EC sucks pretty hard for the most part on these types of things.

[an uncanny otter]

Yeah, EC has some pretty abysmal archive-keeping. It's unfortunate, but trying to find any sort of historical data is frustrating and near-impossible in some cases. :/

[on_wx]

Yeah, EC has some pretty abysmal archive-keeping. It's unfortunate, but trying to find any sort of historical data is frustrating and near-impossible in some cases. :/

During the 2008 federal audit of Environment Canada, they were unable to prove verification rates of their warnings and were weary to start because it was too much work. But agreed to look into the matter.

So, I guess you could interpret that as if they even they don't keep records.

[on_wx]

During the 2008 federal audit of Environment Canada, they were unable to prove verification rates of their warnings and were weary to start because it was too much work. But agreed to look into the matter.

So, I guess you could interpret that as if they even they don't keep records.

Ah yes,

Verification of severe weather warnings

2.61 Environment Canada reports that it issues more than 10,000 severe weather warnings across Canada per year. These warnings are considered the most important product among weather services, as they contribute directly to the Department's objective of enabling the public to protect their safety and well-being. The Department has made commitments to improve the timeliness and accuracy of its warnings. Verifying the accuracy and timeliness of these warnings would allow Environment Canada to better understand their quality and to determine whether its performance is improving over time. The Department could also use the results of verification to improve its science and forecasting process and therefore the performance of its warning program. Publicly reporting on the quality of its severe weather warnings would strengthen Environment Canada's accountability and may increase users' confidence in the warnings they receive.

2.62 Verifying severe weather warnings can be challenging for a variety of reasons. For example, warnings may be issued for specific forecast regions lacking surface weather observation stations that could provide verification data. Severe weather events, particularly severe summer storms, can be small-scale and highly localized, appearing and dissipating quickly.

There is no national verification approach or program

2.63 We expected that Environment Canada was verifying the quality of its severe weather warnings. Based on interviews with department officials responsible for forecasts, warnings, and performance measurement; interviews with regional forecasters; and a review of verification reports, we found that there is no national program or approach for verifying severe weather warnings and assessing Environment Canada's overall performance in delivering them. This information is important as it would help Environment Canada know how good a job it is doing across Canada, whether its current performance meets its own and users' expectations, and whether it needs to improve its services and increase investment in areas such as monitoring and delivery.

2.64 Environment Canada has established a national verification program for its public and aviation forecasts and has made some effort to develop a national program for verifying severe weather warnings. The Department produced a draft report in 2006 analyzing the accuracy and timeliness of summer severe weather watches and warnings across Canada from 2001 to 2003. However, the report was never finalized, as resources were redirected from this initiative to other priorities in the Department.

2.65 In three of the four regions we examined, we found some recent verification of severe weather warnings. On an ad hoc basis, the verifications checked a variety of indicators, such as warning lead-time, forecast accuracy, false alarms, and probability of detection of events. While the approaches used were not consistent among regions, these efforts, along with the Department's national program for verifying public forecasts, could be used as the basis for a national program for verifying severe weather warnings.

2.66 Recommendation. Environment Canada should establish and implement a national program for verifying the quality of severe weather warnings throughout the year.

The Department's response. Environment Canada agrees with the spirit of this recommendation. A full comprehensive verification system would be expensive and likely not cost-effective. Instead, the Department is in the process of finalizing the implementation of a Quality Management System, registered to ISO 9001, which provides the building blocks for a holistic, realistic, and affordable approach regarding program and product verification and quality measurement. The Department is committed to implementing an appropriate mix of measures to understand the performance of its warnings, and there are already efforts under way to improve the consistency of the scientific verification of its warnings. However, the cost, complexity, and scientific challenges of developing and implementing such a system warrants analysis in the context of all other available means of performance measurement that may prove more effective and affordable.

This analysis will be undertaken in fall/winter 2008–09 and will result in the development of costed options to implement a comprehensive performance monitoring and measurement system. This system will have the appropriate mix of scientific verification and information gathering, such as the post-event studies conducted through the Warning Preparedness Meteorologist program (as described in our response to the recommendation in paragraph 2.74) and through Public Opinion Research—both representing critical methods to determine the effectiveness of the warning program.

http://www.oag-bvg.g...31819.html#hd5a

[andyhb]

lol

[on_wx]

lol

I'm sure the false alarm rate is outrageously high. They don't make spotter or weather station reports available unless a high impact event has occurred. Even then, they display the information for 12-24 hours in a severe weather summary, and then take it offline never to be seen again. Sometimes, especially warnings from years past, they would quote CANWARN reports.

Also, they do not make tornado confirmation reports public unless you email them or they release a severe weather summary. Even then, some years my emails have been bounced around departments and offices and they send an incomplete list of confirmations. Also, due to the massive geographical size of all weather forecasting offices, they are unable to confirm several tornado reports. Sometimes they will conduct phone interviews, or send out local government officials to check out damage, but many tornado reports even today go unconfirmed when they are out of range of the weather offices ability to travel to the location.

This tornado list I got is still a great list, but it's incomplete in several areas. According to the list, there were 600 tornadoes confirmed from 1950-2009 in Ontario, but as I mentioned somewhere above, there are a lot of missing tornadoes. Probably in the range of 20-40 by an off-hand estimate. Nothing too huge I guess, but the F3 tornado that killed 9 people in Windsor on April 3 1974 is not on the list. Which is pretty significant I think.

[YHM Supercell]

After looking at the tornado data posted above, I see that the City of Hamilton has 7 "confirmed" tornadoes according to the data that on_wx has posted. However, after doing some further research I have discovered that there are likely quite a few tornadoes missed for the Hamilton area (likely other areas as well) not on_wx's fault but the possibility of incomplete data from EC. An example of EC's incomplete data would be the F1 tornado that hit Stoney Creek(in the City of Hamilton) in 1996. The tornado hit a drive in movie theatre while playing the movie twister. This tornado was not in EC's records.

After looking around the internet at some sites like www.ontarioweather.com I have found that between 1984 and 2001, Hamilton has seen 7 tornadoes. If you add the tornadoes that hit Hamilton in 2005 and on August 24th of this year, that would bring the total to 9 since 1984. And prior to 1984 there were likely other tornadoes, however I'm not sure the exact number. My point is that there are likely alot more tornadoes that have hit areas of Ontario that have gone un recorded.

It would be nice to know the actual number, but we know that wont happen. I would rather see improvement in EC's warning product generation before seeing them confirm every tornado. You have to forecast them before you confirm them

[on_wx]

After looking at the tornado data posted above, I see that the City of Hamilton has 7 "confirmed" tornadoes according to the data that on_wx has posted. However, after doing some further research I have discovered that there are likely quite a few tornadoes missed for the Hamilton area (likely other areas as well) not on_wx's fault but the possibility of incomplete data from EC. An example of EC's incomplete data would be the F1 tornado that hit Stoney Creek(in the City of Hamilton) in 1996. The tornado hit a drive in movie theatre while playing the movie twister. This tornado was not in EC's records.

After looking around the internet at some sites like www.ontarioweather.com I have found that between 1984 and 2001, Hamilton has seen 7 tornadoes. If you add the tornadoes that hit Hamilton in 2005 and on August 24th of this year, that would bring the total to 9 since 1984. And prior to 1984 there were likely other tornadoes, however I'm not sure the exact number. My point is that there are likely alot more tornadoes that have hit areas of Ontario that have gone un recorded.

It would be nice to know the actual number, but we know that wont happen. I would rather see improvement in EC's warning product generation before seeing them confirm every tornado. You have to forecast them before you confirm them

The November 2005 Hamilton tornado is on the data sheet, and the August 24 2011 tornado touched down in Waterloo Region and tracked into City of Hamilton. So going by this list that only includes touchdown points, that would keep City of Hamilton around seven. Which is what "the list" dictates, but not ontarioweather.com's Environment Canada archives research. But still down the 1996 tornado since it has apparently gone unreported even though it was confirmed.

So, City of Hamilton should be at 8 tornado touchdown reports if you include that lost report. Lord knows what number when you factor in all the other apparently "lost" reports, too. Maybe in the area of 12+... from 1792-2009. And to juxtapose this data, several SEMI counties have had 30-40 tornadoes from just 1950-2010.

[YHM Supercell]

The November 2005 Hamilton tornado is on the data sheet, and the August 24 2011 tornado touched down in Waterloo Region and tracked into City of Hamilton. And going by this list that only includes touchdown points, that would keep City of Hamilton around seven. Which is what "the list" dictates, but not ontarioweather.com's Environment Canada archives research. But still down the 1996 tornado since it has apparently gone unreported even though it was confirmed.

So, City of Hamilton should be at 8 tornado touchdown reports if you include that lost report. Lord knows what number when you factor in all the other apparently "lost" reports, too. Maybe in the area of 12+.

You are correct about the August 24th 2011 touchdown in Waterloo Region, however the tornado was in the Region for mabye 1-2km at most. The rest of the track was in the City of Hamilton. It doesnt count as a touchdown point for Hamilton but It deffinitely should count as a tornado because for more than 80% of its duration, it was in the city.

[on_wx]

You are correct about the August 24th 2011 touchdown in Waterloo Region, however the tornado was in the Region for mabye 1-2km at most. The rest of the track was in the City of Hamilton. It doesnt count as a touchdown point for Hamilton but It deffinitely should count as a tornado because more than 80% of its duration, it was in the city.

You're completely right about how it still counts as a tornado in the City of Hamilton, but doesn't go by this data sheet or ontarioweather.com's list of just touchdown points. This is all a mess, really.

I guess it could be pointed out that some of these tornado counts may seen abnormally low because this list only includes touchdown points as opposed to NWS records which tally counties impacted, too. The Aug 24 example is solid because yes that tornado was only in one census division for so long before somewhat long-tracking into another. So, by this data sheet, City Hamilton would not be included, but Waterloo Region would.

Which seems a bit unfair.

In other respects, it could be fair to say this list operates by Environment Canada philosophy. Counties don't exist.

[snowstormcanuck]

You are correct about the August 24th 2011 touchdown in Waterloo Region, however the tornado was in the Region for mabye 1-2km at most. The rest of the track was in the City of Hamilton. It doesnt count as a touchdown point for Hamilton but It deffinitely should count as a tornado because for more than 80% of its duration, it was in the city.

BTW...Welcome to the board!

[YHM Supercell]

You're completely right about how it still counts as a tornado in the City of Hamilton, but doesn't go by this data sheet of ontarioweather.com's list of just touchdown points. This is all a mess, really.

I guess it could be pointed out that some of these tornado counts may seen abnormally low because this list only includes touchdown points. The Aug 24 example is solid because yes that tornado was only in one census division for so long before somewhat long-tracking into another. So, by this data sheet, City Hamilton would not be included, but Waterloo Region would.

In other respects, it could be fair to say this list operates by Environment Canada philosophy. Counties don't exist.

If Environment Canada were to make a table of all tornado touchdown points for areas in Ontario, the list would read.

Windsor-Essex-Chatham-Kent (number of tornadoes)

Sarnia-Lambton(number of tornadoes)

ect ect...because to them Counties are a bunch of rubbish and are not needed when creating a warning.

But back to the point, the data may be a bit of a mess but it is very useful in many ways.

BTW...Welcome to the board!

Thanks very much snowstormcanuck. I run a site with on_wx at www.stormpredictioncenter.ca take a look if you would like to.

[on_wx]

If Environment Canada were to make a table of all tornado touchdown points for areas in Ontario, the list would read.

Windsor-Essex-Chatham-Kent (number of tornadoes)

Sarnia-Lambton(number of tornadoes)

ect ect...because to them Counties are a bunch of rubbish and are not needed when creating a warning.

But back to the point, the data may be a bit of a mess but it is very useful in many ways.

They already use their personally-created warning zones against actual counties to tabulate tornado totals.

[YHM Supercell]

They already use their personally-created warning zones against actual counties to tabulate tornado totals.

Well, nice to know they have that.....I see Hamilton has 2 confirmed tornadoes here. Jeez, who to believe.

[on_wx]

Well, nice to know they have that.....I see Hamilton has 2 confirmed tornadoes here. Jeez, who to believe.

So, seven tornadoes in City of Hamilton from 1984-2001 by one Environment Canada source.

Then, two tornadoes in City of Hamilton from 1979-2004 from another Environment Canada source.

And then seven tornadoes 1792-2009 by another Environment Canada source (my list)

[YHM Supercell]

So, seven tornadoes in City of Hamilton from 1984-2001 by one Environment Canada source.

Then, two tornadoes in City of Hamilton from 1979-2004 from another Environment Canada source.

And then seven tornadoes 1979-2009 by another Environment Canada source (my list)

I've never seen such a reliable source. I wonder who made those maps up. I notice they use the naming "Public Forecast Regions" clevar EC

[on_wx]

I've never seen such a reliable source. I wonder who made those maps up. I notice they use the naming "Public Forecast Regions" clevar EC

I'm about to throw this list out the door, but it's still useful in ways... but just barely at this point.

And where does the 1996 F1 tornado that hit the drive-in about to play Twister factor into all of this?

[YHM Supercell]

I'm about to throw this list out the door, but it's still useful in ways... but just barely at this point.

And where does the 1996 F1 tornado that hit the drive-in about to play Twister factor into all of this?

Probably confirmed it as straight line wind damage. I'm surprised they didnt just confirm Goderich as straight line wind damage over the phone...

[Hoosier]

There are issues/discrepancies with the database here in the states as well. Kinda annoying but hey it's better than nothing.

[on_wx]

Probably confirmed it as straight line wind damage. I'm surprised they didnt just confirm Goderich as straight line wind damage over the phone...

Yeah. I'm a little bummed out by this. Guess it goes with the saying 'if something seems to good to be true it probably is".

[on_wx]

There are issues/discrepancies with the database here in the states as well. Kinda annoying but hey it's better than nothing.

Oh no doubt and I agree. But with Environment Canada you sometimes never know what to believe.

One EC source said 18 tornadoes on August 20 2009, and another said 20 tornadoes then 18 in the same report. Then on my list it says 19.

Wild goose chase.

[on_wx]

Tornadoes by decade...

(As stated above in past discussions, the records I'm using are just one source and vary greatly from other official sources...but the data used to compile this info is the only large info stash on tornadoes in the province. These may be only 3/4 of the official count.)