Giant red zone: Fire danger extreme across Saskatchewan, Alberta

On May 4, Natural Resources Canada indicated that the risk of fire is “extreme” all across Alberta and Saskatchewan.

Danger map shows 'extreme' risk of fires in both provinces

Here's what the fire weather risk looks like on May 4, 2016. Virtually the entire province of Saskatchewan is under an extreme risk warning. (Natural Resources Canada)

As tens of thousands of residents flee from Fort McMurray, Alta., the threat of more fires continues to loom across Alberta and Saskatchewan.

On May 4, Natural Resources Canada indicated that the risk of fire is "extreme" in the two provinces.

A map the federal department produced for Wednesday shows a huge red zone over most of the region.

The Canadian Wildland Fire Information System is a computer-based system that monitors fire danger conditions across Canada.

The system creates a fire danger map based on daily weather conditions such as temperature and humidity.

It also takes into consideration factors like how easy it is to ignite vegetation, how difficult a fire may be to control, and how much damage a fire can do.

Here's what the fire risk map for Western Canada looked like a week ago. Almost nowhere in Saskatchewan was the risk considered "extreme." (Natural Resources Canada)

1 week ago

Last week, fire danger was rated as "low" in places now consumed by fire, like Fort McMurray.

In Saskatchewan, there was virtually nowhere in the "extreme" risk zone.

This time last year

On May 4, 2015, the fire danger map indicated varying risk levels, with the majority of the provinces sitting at "low" to "moderate" risk.

In Saskatchewan, the "extreme" risk zone was limited to the extreme southwest and southern regions. This was before a record-breaking summer in Saskatchewan for wildfires.

A year ago, on May 4, 2015, the fire weather risk was rated as extreme in southwest Saskatchewan, while the north was moderate or low. (Natural Resources Canada)

In 2015, the flames and smoke forced more than  13,000 people from their homes in northern Saskatchewan, making it the largest evacuation in province's history. The total area burned by wildfires in 2015 was 1,719,090 hectares.