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Flood risk increase in some communities

Collin Needlay (standing with oar), Clifford Lomen, Donald Lomen (sitting) and Joachim Klondike (in back of boat) paddle across the flooded section on Fort Liard's main street. Two boats ferried people back and forth to the section cut off by flood waters from the Liard River break-up in 2010. photo courtesy of Roslyn Gardner Firth

Warm temperatures mixed with large amounts of precipitation could mean some NWT communities will experience flooding this spring, suggests hydrologist Shawne Kokelj.

Over the last few weeks the Department of Environment and Natural Resources and its partners in surrounding jurisdictions; the Yukon, Alberta and British Columbia, have been actively monitoring the water levels in major bodies of water which connect to the territory.

Kokelj said residents in smaller communities near the Mackenzie River at Fort Simpson should be watching for large amounts of rainfall and warm weather. The combination could be problematic for residents.

“I can't say I have a formula that will tell me whether or not flooding will happen at any particular location at this point,” said Kokelj. “Anything that influences the rate of snow-melt or adds more water to the system can have a large influence ... rain does both so the potential occurrence and the severity of flooding depends in large part of the weather the next few weeks and how it interacts with water levels and snow pack amounts.”

NWT communities have a history of seeing high-water levels causing spring floods.

In 2010 the uptown section of Fort Liard experienced flooding around one-metre deep. The flooding left many residents struggling to evacuate their homes.

Kokelj released her NWT Spring Water Levels Outlook research and studies report on May 1.

Environment Yukon stated that at the beginning of March the Liard River was flowing with 80-85 per cent capacity, although, those numbers have recently started to climb.

Kokelj said rising water in this area during the spring is not uncommon.

“Alarm bells don't go off for me in regard to the Liard River, but anything can happen,” said Kokelj. “Ice jams are unpredictable in terms of the potential for flooding, however we have an incredible number of eyes on the ground as well as community members who are providing us with information, which is helpful.”

Ice jams move from south to north and are one of the most problematic variables when it comes to the risk of flooding, added Kokelj.

“You're getting warmer water and potentially warmer air temperatures pushing ice into areas where you may be seeing more solid ice,” she said.

The water level report was released to the public two-days after evacuations in the Northern Alberta hamlet of Peace River.

The warnings in the Alberta hamlet cleared out more than 200 people, ice jams were to blame as a major source of the flooding.

In Alberta Environment's spring outlook, the report states the Peace and Athabasca River experienced a high volume of water between November, 1 2017 and April 1, 2018 resulting in levels which are above average to much above average.

“As of April 1, 2018 the water was 115-120 per cent of normal,” stated the report.

The Peace River and Lake Athabasca are two major bodies of water connected to the territory via the Slave River. Any overflow from the two flows through the Slave River near communities like Fort Smith and Hay River. From there, water enters through the Peace/Beaufort Delta region.

However, Kokelj said Fort Smith is not at risk.

“Fort Smith is definitely not one of the communities at risk because of their elevation level,” said Kokelj. “It's a really complex system, but in many years they may want ice-jam floods because that is what can help regenerate some of the lakes and wetlands in that region ... even if the Slave River levels rise a lot, there are no communities that are prone to flooding.”

Regions experiencing unique weather patterns

Not all of the areas in the territory are experiencing the same patterns.

Wildfires in the North Slave region of the territory have left the region dry for a number of years and increased the risk of wildfires in the area.

Last year the Sahtu, Decho and South Slave regions experienced an active wildfire season.

Information provided by ENR to Yellowknifer indicates the 2017 season was the fifth most active wildfire season in over 30 years. The territory saw 262 wildfires which over 860,000 hectares of land.

As the weather continues to dictate our everyday life climate change remains one of the more controversial solutions as to why our environment shows signs of inconsistency. Kokelj's data assures her these cycles of wetter periods in the southern region of the NWT and the dryer periods to the North remain the product of climate cycles.

“The wetter and dryer regions in the territory are part of regular cycles that the territory will be looking at and putting into a bigger context,” said Kokelj, who worked for Indigenous and Northern Affairs Canada from 2001-2013. “Certainly not all regions react the same as others, so to throw the NWT under one statement is not useful.”