Calgary city officials anticipate water levels on the Bow River to drop beginning Monday after a heat wave contributed to a rapidly melting snowpack last week.
Flood watch advisories put in place for the Bow River upstream of Banff, including Lake Louise and the Pipestone River, were lifted Monday.
This comes as much of Banff National Park was placed under a winter storm warning on Monday, with up to 40 centimetres of snow expected to fall in some areas.
Those lower temperatures are expected to help with river levels downstream in Calgary.
“We’re going to start to see drops in the river level, including on the Bow River starting probably (Monday) afternoon as the temperatures have cooled off and that snowmelt slows down,” City of Calgary river engineering team lead Sandy Davis said.
“There may be temporary local increases in river levels, and then they’ll come back down, but there are no flood concerns over the next week or so.”
John Pomeroy, Canada research chair in Water Resources and Climate Change, said those sweltering temperatures caused the snowpack in the higher elevations to melt at a rate faster than he’s seen before.
“To have that kind of very high snowpack at a time of extremely high temperatures that were held for a whole week was quite rare,” Pomeroy told Global News.
“To get 200 millimetres of snowmelt in a week is phenomenal.”
Upstream in Banff, river levels peaked over the weekend at 3.2 metres in height and have slowly dropped to 2.9 metres on Monday.
The rising river levels prompted town officials in Banff to issue warnings to residents and visitors to stay away from the river banks.
“It was certainly concerning last week because we saw the river rise significantly in a very short period of time, including overnight, which is something we typically don’t see,” Banff emergency management director Sylvio Adamo said.
A boating advisory remains in effect in Calgary, and some underpasses near the Bow River remain closed due to the speed and height of the river. Some pathways in Fish Creek Provincial Park did see some minor flooding on Monday.
“The way the river is right now, it really increases the risk for anyone wanting to go on it,” said Calgary Fire Department public information officer Carole Henke.
“We’re hoping people will abide by the boating advisory and stay off the river until such time that the advisory is lifted.”
CFD’s rescue boat was put into use on Monday after city bylaw officers decided to check out a homeless encampment along the river that had access blocked due to the high water levels. According to the city, one person was rescued from the area without any injuries.
According to Henke, that boating advisory could be lifted as soon as this week but that ultimately depends on how significantly the water levels on the river change over the coming days.
Although there is some rain in the forecast, city officials said there isn’t any concern that enough could fall to cause flooding.
“The City of Calgary doesn’t flood over its riverbanks from light or moderate rainfalls, which is generally what we’re expecting over the next week,” Davis said.
“So we’re expecting rivers to continue to decrease with potential localized increases from drainage and runoff during those rain and thundershowers.”