After a long, snowy winter, spring is sure to follow, and with it comes the thawing of snowpacks and ice, known as the spring freshet. In BC, this usually occurs from April to early July, depending on the volume of snow. Rapid snowmelt causes waterflow to swell and surge rapidly, blasting its way through natural stream channels as it makes its way down hills and mountainsides, collecting in rivers below. When channels can’t sustain an overflow, it can result in flooding, destabilization of soil and rocks; and rapidly running rivers, full of debris. Powerful overflow has been known to cause landslides and road washouts. Besides snowpack, another contributing factor to flooding is critical weather factors that occur simultaneously with snowmelt, such as periods of early hot weather or significant rainfall. Did you know that the snowpack produces 20-40% of the flood risk, while weather factors 60-80%?
Why should you care? If you live, work, or play near mountains, streams or rivers, like we do in Hope, it’s important to keep these factors in mind:
· The fast-flowing undercurrent on rivers doesn’t stay frozen as long as the surface does, meaning an ice crust on top that can look deceptively stable: it is not! Keep children and dogs off the ice and educate your children about the dangers of thin ice.
· Stay away from riverbanks, as the ground will often be very slippery or water may have eroded the soil or sand under the surface, which can make the ground you’re standing on give way beneath you.
· Boating on rivers during freshet isn’t safe. The water flows at an extreme rate and is full of debris that the runoff brings with it, such as branches and even whole trees. Be cautious boating on lakes during this time as well; floating debris can be carried into lakes from tributaries.
· Keep aware of signage indicating avalanche zones. Rockfalls and landslides have occurred on every highway surrounding Hope. Exercise caution and continuously scan ahead as you drive, as rocks and mud on the highway during this time aren’t unheard of. In fact, during the last few years, the Fraser Canyon’s Highway 1 has had several highway closures during the freshet from reasons ranging from muddy washouts to massive rockslides that closed the highway for days.
· If a slide has taken down powerlines, BC Hydro advises to stay back at least 10 metres and call 911 to report. If you come across a downed powerline, always assume it is live, and never drive over it. BC Hydro suggests remembering these 3 words: Down, Danger, Dial!
· Keep aware of water levels by checking out the BC River Forecast Centre for flood warnings and freshet conditions. A great app for anglers and boaters to check river conditions before heading out is the RiverApp. The Government of Canada Environmental and Natural Resources also has a website featuring Real-Time Hydrometric Data. Search by province for real-time water levels and discharge data.
There’s no better place than Hope, Cascades & Canyons to watch spring bloom! Stay safe and enjoy the feelings of renewal and rejuvenation that the changing seasons bring!