Environment Canada says there’s a risk of a tornado in western Renfrew County on Tuesday, and has issued a rainfall warning and severe thunderstorm watch for most of western Quebec lasting through early Wednesday.
The severe thunderstorm watch, which includes the tornado risk, covers Renfrew County west of Petawawa and Barry’s Bay on Tuesday afternoon and evening.
A tornado watch is issued when there’s a storm approaching with conditions that could produce a tornado. A warning goes out either when a tornado sighting has been reported or when there’s sufficient evidence to suggest a tornado is on the way.
When a tornado forms, people are advised to stay away from exterior walls and windows, ideally going to a basement or the ground floor. They should also get out of vehicles.
Along with the tornado risk and lightning, Environment Canada says these storms can bring strong wind gusts, hail and heavy rain.
Renfrew County also has a special weather statement about 60 millimetres as the top-end forecast from late afternoon into Wednesday. A significant amount of that could fall in an hour and trigger a rainfall warning there.
Pembroke’s daily rain record of about 26 millimetres on Aug. 27, 1997 could be broken.
Up to 75 mm under rain warning
Another thunderstorm watch covers the Outaouais, except for Gatineau and its easternmost communities such as Grenville, Places east of Quyon could get 20 to 40 millimetres of rain and to the west, about 50 millimetres.
Those more western communities are under a rainfall warning.
If a few thunderstorms hit there, more rain than that could fall. The warning floats 75 millimetres of rain as a possibility.
Ottawa is forecast to get 15 to 25 millimetres of rain overnight.
Environment Canada warns the rain could cause flash floods and water pooling on roads.
In preparation for a flood, Environment Canada advises people to learn how to shut off their utilities and safeguard heating equipment, along with keeping sandbags and emergency kits.
In the case of a flood, don’t try to walk through the water ��— even if it looks shallow — and also avoid driving through it.
Precipitation trends vary across the Ottawa-Gatineau region: Ottawa was having a drier year than usual until early summer, while Kingston is still about 200 millimetres below average so far this year.