Ice breaks and fast-flowing water possible as Yukon Energy continues to lower Marsh Lake levels.
Yukon Energy is asking Yukoners to avoid going on the ice on Schwatka Lake starting today. Water levels on Schwatka Lake will fall over the next week as Yukon Energy continues to increase the amount of water flowing through Miles Canyon and the Whitehorse dam, in an effort to lower water levels on Marsh Lake.
Yukoners are being warned that lower water levels on Schwatka Lake may cause ice along the lake’s shorelines to break and for there to be unpredictable ice conditions. Water flowing under the ice surface is also likely to move faster than before.
Yukon Energy started increasing flows at the Whitehorse dam earlier this month after Yukon government’s March 2021 Snow Survey Bulletin highlighted snowpack levels in the Southern Lakes region to be 172% of normal. At the time, Yukon Energy also forecasted that in case of a wet spring, water levels on Marsh Lake could peak at 656.82 m – similar levels to those reached in 2004, but 52 cm below water levels reached during the 2007 flood.
On March 19th, Yukon Energy opened all 30 gates at the Lewes River Control as an initial measure to lower levels on Marsh Lake. As of 8:00 this morning, Marsh Lake levels were at 654.61 metres above sea level and 60 centimetres lower than lake levels on March 1, 2021*.
Every spring, Yukon Energy draws down lake levels on Marsh Lake by generating hydroelectricity at the Whitehorse dam. This makes room in the lake for rain and spring melt. Water levels in Marsh Lake typically reach their lowest level in late May when they fall to around the Low Supply Level of 653.796 m – the lowest level allowed under Yukon Energy’s current water use licence. This spring, because of high snowpack levels, Yukon Energy plans to apply for an emergency amendment to its water license to draw Marsh Lake levels down 10 cm lower than the existing low supply level.
Yukon government will release their next Snow Survey Bulletin in April. Yukon Energy will provide an updated peak water level forecast for Marsh Lake shortly thereafter.
*Corrected. A previous version stated March 1, 2020.
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