The Oldman River is expected to reach a peak flow of 700 cubic metres per second early Thursday morning.
That’s well short of the predicted peak flow of 1,700 originally predicted by Wednesday night.
During the 2013 flood the peak flow was 2,250 cms. In 2005 it was 1,750 and in 1995 it was 2,750.
“They’re not going to be as high as initially predicted,” Evan Friesenhan, director of the river forecasting section of Alberta Environment and Sustainable Resources Development, said during a news conference at 4 p.m. Wednesday.
The storm originating out of the United States was expected to dump 200 mm of rain in the Crowsnest Pass.
Alberta Environment on Tuesday issued a flood advisory for the entire Oldman River basin, when water levels were expected to be higher this year than 2013.
“We did receive a significant amount of precipitation in the southern portions of the province over the evening and through the morning today,” Friesenhan said. “The bulls-eye of heavy precipitation was not experienced over as large an area overnight as was forecast but was centered over the Waterton Lakes area. Amounts up to 170 mm were experienced, but in a small area.”
“As you moved out from that bulls-eye the precipitation amounts did drop off fairly significantly.”
The forecast 200 mm of rain did not materialize over the larger area as was predicted.
Friesenhan said snow at elevations above 1,600 metres was reported.
“That also had an impact on decreasing the amount of water that was rushing into our rivers,” Friesenhan said.
The peak flow of the Oldman River at Lethbridge, which Tuesday was expected to be 4,500, is now expected to be 1,800 cms.
“Although that does suggest a smaller flood we are most certainly having significant impact to Albertans in the Oldman basin,” Friesenhan said.
River-related flooding is occurring along the tributaries to the Crowsnest River, Willow Creek through to the Chain Lakes reservoir, Waterton River, Belly River and Waterton Lakes area.
Claresholm, Coalhurst, Cardston, Blood Tribe, Medicine Hat, Crowsnest Pass, MD of Willow Creek, City of Medicine Hat and Lethbridge County have declared a state of emergency.
The City of Lethbridge, Piikani Nation and Town of High River have set up emergency operations centres but have not yet declared a state of emergency.
“Each of these communities that have been impacted by this event are actually performing extremely well,” said Stephen Carr, director of central operations for the Alberta Emergency Management Agency. “They’re responding effectively and timely to the needs of their citizens.”
Carr said there have been few requests of the agency for support.
“The communities are showing tremendous resiliency,” Carr said.
The water elevation in the dam is 1,117.9 metres, which is half a metre below the full supply levels.
At 4 p.m. the outflow from the Oldman Dam was 750 cms.
“They are doing their best to accommodate the in-flows and minimize the impacts downstream,” Friesenhan said.