Watches/Warnings
--Definitions
Current Conditions
Radar/Satellite
Lightning Images
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Definitions of Weather
Watches and Warnings
Environment Canada issues many different types of
watches/warnings for adverse weather conditions. Below is a basic explanation of
these although in fall and spring combinations of all can occur.
General Watches & Warnings
| Weather Watch: |
Conditions
favourable for development of severe weather in
watch area during posted time frame. Keep your eyes and ears open for changes. |
| Weather
Warning: |
Severe weather is occurring or will be occurring in the near
future. Motion, direction, duration & composition are given for specific events.
Listen to weather statements and be prepared to take cover. |
| Weather Advisory: |
Actual/expected conditions may cause concern but not
serious enough to post warning at this time. |
Watches/Warnings for Winter
| Frost
Warning: |
When temps forecast to fall near or below
freezing during growing season. |
| Freezing
Rain Warning: |
Extended periods of freezing rain are
expected that can damage trees, overhead wires and cause hazardous driving conditions. |
| Heavy
Snow Warning: |
Expect 15cm or more in 12 hours or less. |
| Snowsquall
Warning: |
Local snowsqualls producing large amounts
(+10cms or more) in traditional snowbelt areas. |
| Blizzard
Warning: |
Snow or blowing snow, with severe wind-chill
and reduced visibility(>1km) for 4+hrs. |
| Winter
Storm Warning: |
When 2 or more winter warning conditions
met (eg: wind + snow) |
| Wind-Chill
Warning: |
Very cold with windy conditions creating
hazardous outdoor temperatures. |
| Cold
Wave Advisory: |
Temperatures to drop more than 20°C within
18hrs. |
| Flash
Freeze Warning: |
When forecast conditions will likely produce
rapid ice formation on road surfaces (rapid temp drop and significant precipitation prior
and during event). |
|
Blowing Snow
Warning: |
Extensive reduced visibilities
in blowing snow with whiteout conditions expected in many areas.
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Watches/Warnings for Summer
| Severe
Thunderstorm Watch: |
Favourable conditions for severe
thunderstorms with large hail, heavy rain, intense lightning or damaging winds. |
| Severe
Thunderstorm Warning: |
Developed storm is producing some or all of
watch conditions above. Tornadoes may also be produced in severe thunderstorm
environment. |
| Tornado
Watch: |
Favourable conditions for development of
tornadoes |
| Tornado
Warning: |
One or more tornadoes are on the ground,
forming or detected on radar. Listen to weather statements and take cover in lowest point of house or if
outside, ditches/culverts if in the path. |
| Heavy
Rain Warning: |
When rainfall can cause flooding. Expect
50mm over 12hrs or 80mm in less than 24 hrs. |
| Wind
Warning: |
Steady winds at/above 60km/h or gusting to
90km/h or more for 1 hour or more. |
| Dust
Storm Advisory: |
Mainly prairies where dust and high winds
reduce visibility to <1km. |
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