Landscape Ontario
Snow and Ice Symposium
Southern Ontario’s Wacky Winter Weather
02-September-2010
Rob Kuhn
Severe Weather Meteorologist,
Ontario Storm Prediction Centre
Toronto, Ontario
Outline
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Winter weather stuff
Watch, warning and weather statements
Weather radar
Winter Storm Tracks
Major Winter Snowstorms
Major Winter Ice Storms
Lake Effect Snow
Questions?
Job Profile and Education
Environment Canada
-Ontario Storm Prediction Centre•Honours
BSc (UWO)1984
•MSc Meteorology (U of T) 1987
•Government Operational Meteorology Course 1987-88
•Internship Winnipeg 1988-1989
•Internship Toronto 1989-1990
•Lead/Severe Weather Meteorologist 1995-present
•Continuous learning (courses, teaching, R&D)
•Outreach
•Shift work 24/7
Your income taxes help pay my salary!
Some Winter Weather Stuff
http://www.islandnet.com/~see/weather/graphics/photos/glsnow.gif
Lake effect snow a major contributer!
Some Winter Weather Stuff
Snowfall amounts Southern Ontario
(not snowbelts)
Average total winter snow … about 100-150 cm
Average number of days with snow .. About 65
Snow Season .. Nov 15 to April 15
Tr-2 cm - 1-3 times a week
2-10 cm – 2-5 times a month
10-20 cm – 2-4 times per winter
20-30 cm – once every 2-3 years
Close to 30 cm – January 1999
40 cm or over – March 07-08, 2008
Biggest Ever – 76 cm Nov 24-25, 1950
Many small snowfalls with drifting
snow from lake effect flurries
Some Winter Weather Stuff
Snowfall amounts Southern Ontario Snowbelts
Average total winter snow … about 200-300 cm
Average number of days with snow .. About 90
Snow Season .. Nov 01 to April 15
Tr-2 cm - 3-5 times a week
2-10 cm – 2-5 times a month
10-30 cm – 5-10 times per winter
30-50 cm – 1 event annually
50 cm or over – probably 1-2 times each two years
Biggest snows - 200 cm over 2-3 days
Many snowfalls with drifting snow
from lake effect flurries and
snowsqualls
Some Winter Weather Stuff
Blowing And Drifting Snow
Average winter wind speed = 15 km/h
Strongest winds from SW-NW = 50 km/h gusts common
Max winter wind speed = 60-70 km/h
Max winter wind gusts = 80-90 km/h
Highest gust on record = 119 km/h March 30, 1981
Fresh snow drifts with 15-20 km/h winds
Fresh snow blows around starting with 30-40 km/h winds
Whiteouts can be an issue with 40 km/h or more winds
Some Winter Weather Stuff
Freezing Rain In Southern Ontario
Average number of freezing rain events … 5
Usual amount of freezing rain .. 1-5 mm
Large ice storms (5-10 mm) - once every couple of years
Major Ice Storm (>10 mm) – once every 5 years
(ice pellet concrete event April 2003)
Winter Severe Weather
(and types of warnings)
Blizzards – heavy and blowing snow, high wind chills
 Snowfall – 15 cm or more in 12 hrs
 Snowsqualls – lake effect snowstorms
 Freezing Rain – 2 or more hours - icing
 Strong Winds – 60 Gusting to 90 km/h or more
 Heavy Rain – 50 mm/24 hrs
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Weather Watch and
Weather Warning
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Severe Weather Watch
-the potential for severe weather
* Be Alert *
Severe Weather Warning
- severe weather will soon occur or is
occurring *** Take Action ***
Winter Storm Watch
Potential of Winter Storm Within 1-3 Days
Winter Storm Watch for:
Kitchener – Cambridge – Region of Waterloo.
A low pressure area from Texas is moving northeast towards Southern Ontario and is
expected to intensify into a winter storm as is moves in Thursday.
Current indications show that snow from this developing winter storm will move into
the region beginning tomorrow afternoon. The snow may change over to freezing rain by
Friday morning as the storm centre passes by just to the south of the district.
Significant amounts of snow and freezing rain are possible from this developing storm.
There is still some uncertainty as to the exact track of this storm so actual snow and
freezing rain amounts may change accordingly.
Travelling conditions are expected to deteriorate by tomorrow evening with hazardous
driving conditions quite possible. Motorists should alter travel plans accordingly.
Environment Canada is closely monitoring this situation and warnings may be issued as
required.
End/Kuhny
Snow Squall Watch
**New 2009-2010**
Potential of Snow Squalls Within 18 hrs-2 Days
 Localized
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Lake Effect Snow Storms
15 cm or more snowfall in 12 hours
visibility in snow squall < ½ km for 3 or more hours
= from wind and/or heavy snow
 Waterloo
Region usually gets ~ 5 of
these per winter
= 20-30 events/winter in snowbelts
Snow Squall Watch
Potential of Snow Squalls Within 1-2 Days
Snow Squall Watch for:
Kitchener – Cambridge – Region of Waterloo.
Snow squalls are expected to develop after midnight tonight as a strong cold
northwesterly flow of fresh arctic air picks up moisture from the relatively mild waters of
Lake Huron.
Local snowfall amounts of 15 cm are quite possible overnight into Thursday morning in
the strongest snow squalls. In addition strong northwest winds gusting to 70 km/h will
cause frequent near zero visibility in blowing snow.
Dangerous winter travelling conditions from whiteouts in bursts of heavy snow and
blowing snow are anticipated. Motorists should alter travelling plans accordingly.
The threat of snow squalls will end Thursday afternoon as winds diminish.
Environment Canada is closely monitoring this situation and warnings may be issued as
required as the event draws closer.
End/Kuhny
Winter Weather Warning
Severe winter weather imminent or occurring
14-Jan-2007
Snowfall warning for:
Kitchener – Cambridge – Region of Waterloo.
A strong low pressure system moving from Texas through Ohio to
New England will bring 15 cm of snow and ice pellets overnight and
Monday. There is also a chance of some freezing rain.
This may be quite a high impact storm as most areas have had little
or no snow or freezing rain until now. Motorists should exercise
extreme caution and be prepared to allow much extra time to reach
their destination if travel is absolutely necessary. Dangerous winter
driving conditions are likely..especially during the Monday morning
hours when the snow and freezing rain may be heaviest.
End/Lee/Kuhn/OSPC
Special Weather Statement
Hazardous winter weather imminent or occurring
Warning Criteria not quite met
WOCN11 CWTO 070939
Special weather statement Issued by Environment Canada Ontario region.
4:39 AM EST Wednesday 7 November 2007.
Special weather statement issued for..
London - Middlesex
Oxford - Brant
York - Durham
Huron - Perth
Waterloo - Wellington
Dufferin - Innisfil
Grey - Bruce
Barrie - Orillia - Midland.
..The first widespread lake effect snow event of the season..
Lake effect snow and rain showers which developed to the Lee of Lake Huron and
Georgian Bay in a wake of a departing fall storm will continue today. At 4:30 AM radar
indicates the heaviest activity between Collingwood and Innisfil and then down to
Markham. Some communities inland from the southeast shores of Georgian Bay and Lake
Huron may have received accumulation of 5 or so centimetres of wet snow. Another 5
centimetres are expected today. It should be emphasized that these amounts will be
very localized and any snow which falls will be moisture-laden and may melt and
quickly compact As it contacts the warm ground.
Nevertheless.. This could make for some slippery driving conditions in time for the
morning commute today especially on highway 400.
Listen for further statements. Additional information may also be found by
consulting the latest public forecast.
END/TUGWOOD/ROS
Winter Weather Effects

Often high impact
–
Poor road conditions from heavy and blowing snow
Numerous accidents (also from poor driving habits)
Ice accretion from freezing rain
Flooding during sudden thaws with rain
Snow days (work and school)

Have an Emergency Kit in the car and dress appropriately
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flares
shovel
flashlight/candles/matches
blanket/warm clothes/boots
bottled water/granola bars
Cell phone/BlackBerry
Weather Radar
Radar transmits beam out horizontally
 Receiver at radar station picks up some
return signal reflected off of rain, snow,
hail
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Weather Radar
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Main Problem:
-Earth surface is curved
-Radar beam goes out fairly straight
-Hence looks at precipitation aloft in
areas away from the radar
†
Weather Radar
Another problem:
Snow, rain and
wet snow reflect
differently
= have to adjust
for this all the time
= snow rate
makes rain echoes
look much heavier
Weather Radar
More problems
= heavy rain/snow near the radar can block the radar beam
from detecting more distant precipitation
= radar will show precipitation aloft even if it dries before reaching the ground
Weather Radar
Radar beam too high
= beam can go above the clouds and miss the precipitation
= can be an issue with snowsqualls
Weather Radar
More information found at
http://www.msc-smc.ec.gc.ca/cd/factsheets/weather_radar/index_e.cfm
Weather Radar
Anomalous propagation
= beam forced down to the ground on clear calm nights
= radar “sees” the ground
It was a clear night!!
MAIN WINTER STORM TRACKS
Phil’s Arctic Iceboat
Alberta Clipper
Colorado Low
Texas/Louisiana
Low
East Coast Low
Winter Storms
Anatomy of a Winter Storm
-10°C
Flurries
10°C
Winter Storm Tracks
Alberta Clipper
10-20 cm snow
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2-5 cm snow
Showers
Flurries (Trace - 2 cm)
Often windy
Winter Storm Tracks
Colorado Low
15-30 cm
snow 
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Flurries (Trace - 2 cm)
Usually windy
Rain/showers
2-5 cm snow/Ice pellets
Tr-5 mm freezing rain
Another Major Winter Storm – Sunk the Edmund Fitzgerald in 1975
Winter Storm Tracks
Texas/Louisiana Low
20-40 cm
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snow 
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Flurries (Trace - 2 cm)
Usually windy
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2-10 cm snow/Ice pellets
Tr-5 mm freezing rain
Heavy Rain/showers
Thunderstorms possible
Winter Storm Tracks
East Coast Low
20-60 cm
snow
Light snow for KW
(2-5 cm)
Usually windy
Isolated flurries (Trace)
Usually windy
Waterloo Region
brushed by these
storms
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Winter Storm Tracks
How can we get a big dump in
Southern Ontario???
Winter Storm Tracks
Big Snowstorms For Southern Ontario

15-30 cm
snow
L
Texas Low passes south of us
Snow – freezing rain - snow
Usually 1 of these each winter
This track more rare than
before 1980
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2-10 cm snow/Ice pellets
Tr-5 mm freezing rain
Heavy Rain/showers
Thunderstorms possible
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Very Heavy Snow
Very Heavy Snow
Very Heavy Snow
Bracebridge Dec 2009
100-200 cm snow in 2 days
Photo courtesy George Kourounis
Winter Storms
How Can We Get An Ice Storm In
the Tri-Cities?
Freezing Rain Formation
Warm above freezing air layer
above cold air near the ground.
Snow
Rain
Freezing Rain
Winter Ice Storm Tracks
Major Ice Storms For Waterloo Region
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A tale of two or three Texas Lows
- Passing just south of us
- 2-3 periods of freezing rain
- one of these types every 2-3 years
- no change over to rain
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2-5 cm snow/Ice pellets
 5-25 mm freezing rain
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Major Ice Storm
This one caused major damage in
Eastern Ontario and Quebec
A Major Ice Storm
Jan 1998 Ice Storm – 10 cm Ice Accretion
Freezing Rain
Freezing Rain
Freezing Rain
Ice accumulation heavy enough to bend entire trees!
Snowsqualls
Lake Effect Snow
Waterloo Region
Lake Effect Snow
Waterloo region is on the edge of the Lake Huron snowbelt
• Cold arctic air picks up moisture from Great Lakes
• Winds blow in moisture and flurries to our area
• Heaviest lake effect snow usually just to our West and North
• Most common snow amounts for us .. Trace to 2 cm
• Snowsqualls – local lake effect snowstorms with heavy snow and/or strong winds
•
There are exceptions though!!!!
Snowsqualls
Lake effect snow in one area depends on the wind
direction and speed!
Remember – very local snowstorms
Waterloo Region gets several snowsquall events
each year!
Lake Effect Snow
Southwest winds
Usually trace or nothing
Different story Niagara/Ern Ont/Bruce/Parry Sound
Lake Effect Snow
West winds – usually tr-2 cm
Local 30 cm near lakes
Lake Effect Snow
Northwest winds – best direction
- 5-10 cm often occurs
Lake Effect Snow
Northerly winds
“Traditional case”
Lake Effect Snow
East winds
usually < 2 cm Kitchener
15-30 cm Hamilton into GTA
Snowsqualls
Kitchener – March 2007
Snowsqualls
Kitchener – March 2007
Lake Effect Snowsqualls
Southern Ontario 09-December 2009
Long and narrow storms
Snowsqualls
Low visibility and heavy snow bursts
Snowfall rates of 2-5 cm per hour
Snowsqualls
Very local – 5 km away it could be sunny!!!
Snowsqualls
In the snowbelts huge drifts can
be a problems!
Snowsquall in Action
Blowing and drifting snow !
(Courtesy Tom Stefanac)
Blizzard
Blowing snow < 1 km
visibility
High wind chills -25 C
Wind speed 50 km/h
For 4 hours or more
Last blizzard here was March 1993.
We were close to a blizzard early February 2007.
Strong Winds
Flooding
-can occur in all seasons-
Outlook Winter 2010-2011
Winter colder than average.
Outlook Winter 2010-2011
Winter – near average total precipitation.
Outlook Winter 2010-2011
Winter typically starts near Dec 01
US outlook – near average
My guess – near average temperature
- near average rainfall
- near average total snowfall
It will seem quite snowy
compared to last year!
We’ll see what happens!
Some Weather Information Sites
http://weatheroffice.ec.gc.ca
http://weather.uwaterloo.ca
http://www.vaughanweather.com
http://www.ontarioweather.com
http://www.msc-smc.ec.gc.ca/information_publications_e.html
Questions?
A Major Winter Storm
Hard to scrape the car, eh??
The Ontario Storm Prediction Centre
Look
at that
hair!!!
Yeahhh! Kuhny got the forecast right! (1981)
Cheers!