Municipalities along the major riverways affected by flooding last year held public information meetings with residents on current conditions as spring-breakup season approaches.
The Town of Hay River hosted a public information meeting at the community hall of the Hay River Community Centre for about 20 people on April 20.
Town SAO Glenn Smith, Director of Protective Services Travis Wright, and Coun. Robert Bouchard gave an overview of what the town knows so far with the ice break up season expected to take place sometime between the last week of April and the second week of May.
The newest developments include results from snow surveys recently provided by the GNWT Department of Environment and Natural Resources, ice-thickness measurements conducted by the town and water levels in nearby lakes and rivers.
All measures indicate excessive water in Hay River’s water basin.
“Our snow load for our water basin is anywhere from 108 per cent normal to 140 per cent normal,” Wright said. “By comparison to last year [where] we had 120 per cent normal.
“We are in the same range and it depends on the range in the basin but there’s some with more and some that have less.”
Town officials said the water level of the Chinchagua River - the main tributary that feeds into Hay River from Northern Alberta - is a metre below normal this year when it had been higher than that last year.
As daytime temperatures warm up this week above O C, however, water levels are expected to rise higher as higher than normal snow levels melt.
“One thing that has gone down is the Great Slave Lake (water level) but it’s still high,” Wright said.
“What all of that means is that we have similar conditions to last year where we should be expecting to see a large amount of water come down through the Hay River.”
Ice measurement thickness, which involves drilling 40 bore-holes within municipal boundaries, appeared “close to average thickness and a little bit above average but very similar to last year.”
Territory’s on-the ground snow surveys
Every year the territorial government conducts on-the-ground snow surveys across the territory between mid-March and early April to measure snow water equivalent (SWE), the amount of water obtained from a given area if all snow is melted.
Jessica Davey-Quantick, a spokesperson with ENR said in a recent email to the Hub that SWE is only one of several factors that determine spring water levels.
“The potential and severity of flooding will depend in large part on the weather over the upcoming weeks and how this interacts with existing ice conditions, water levels and snow pack amounts,” she said.
Other factors contributing to spring flood season include ice jams, the rate of melt of ice and snow, gradual versus quick melts, rain on snow or ice events, how wet the ground was in the fall and snow pack.
The municipality’s completes annual ice measurements every year and water levels in the South Slave and Northern Alberta are taken into consideration.
Data collected from these various sources help the municipality understand what spring breakup conditions may be like and can be used to create future modelling.
Historical precedent
Part of the presentation also included some reference to past flooding seasons, especially last year when there were higher than usual water levels.
Smith noted that most of the flow last year pushed through the West Channel and damage was very minor to areas around the municipality, including residential properties.
“There was $150,000 worth of damages last year to town infrastructure,” Smith reported. “We did take advantage of the GNWT’s Disaster Assistance policy and received $100,000 back.”
A full evacuation order in the most flood risk areas of town - Vale Island and the West Channel - would impact about 400 people that live in those neighbourhoods.
The Town is set to hold another information session at 7 p.m., Tuesday, April 26 at the fire hall.