Hazardous Weather Outlook:
Definitions of Hazard Levels and Their Associated Triggers

Hazard Level
0
1
2
3
4
5
Threat to life or
property and/or
economic impact
Nil
Minimal
Small
Medium
Significant
Very
Significant
 





Grassland Fire Danger Index


Very High
Extreme
Ongoing Fires

Heat Index (0F)


100
105 for 3 hours/
Advisory
110 for 3 hours/
Warning
110 for 3 hours/ Warning
for 3 days
Wind Chill (0F)


0
-15 for 3 hours/
Advisory
-25 for 3 hours/
Warning
-25 for 3 hours/
Warning
for 3 days
Blowing Dust
or Smoke



  Blowing Dust Advisory
(3/8sm - 1sm)
Blowing Dust Warning
< 3/8sm
Other Obstruction
to Visibility (statute miles)
Nil
Obstruction  to Visibility
in grids
Patchy 1/2sm
Advisory
Widespread
<1/8sm

Wind
(non-convective)


Advisory High Wind Warning
High Wind Warning
for 3 hours
or more
Hurricane Force
Frost/Freeze Nil
Frost
mentioned
Frost
Advisory
Freeze
Warning


Lightning
Nil
Thunder mentioned




Hail
Nil
Below Significant
Weather Alert
Significant Weather Alert
Severe Hail Likely
>= 2 inches
> 3 inches
Wind
(convective)
Nil
Below Significant
Weather Alert
Significant Weather
Alert
Severe Wind Likely
75 mph
Derecho
Tornado
Nil

Cold Air
Funnels
Chance
Likely Tornado < F4
F4-F5
Winter Weather
Nil
Mentioned
Below Winter Weather
Advisory Criteria
Advisory
or Watch
Warning
Paralyzing Winter Weather
(ie., 1 inch or more ice or
blizzard w/ heavy snow)
River Flood
Nil

Action Stage
  Likely
Flood Warning
(minor-moderate)
Major
Flooding
Record Flooding
Flood/Flash flood
Nil

Flood Warnings Possible
(FLW)
Likely Flood Warnings (FLW);
Possible Flash Flood Warnings (FFW), Flood/Flash Flood Watches (FFA)
Widespread Flooding,
or high probability of Flash Flood Warnings (FFW)
Dam Break/
Catastrophic Flooding

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