A grizzly bear is making a den in the area, prompting a closure north of Bow Lake in Banff National Park. (Parks Canada)

An area north of Bow Lake in Banff National Park has been closed to protect a female grizzly denning in the area.

Believed to be about 8.5 years old, the bear was observed with a large male grizzly in the spring, so officials are hopeful she may emerge with a litter of cubs in spring 2021.

"Noise or disturbance over the winter, however, may cause her to miscarry or lose newborn cubs," reads a notice from the province.

"This area closure will give this bear and her potential offspring the best chance to survive and thrive. Reproductive age female grizzlies are critical to the long-term survival of the grizzly bear population in the mountain national parks."

The areas closed include Hidden Bowl and Jimmy Junior Bowl on the east slope of Mount Jimmy Simpson, along Highway 93.

Anyone who violates the closure could face a fine of up to $25,000.