Southern Lake levels: Update 11, 8-July 2021

Hi All,

This is the 11th email update sharing information about the flood situation for the Southern Lakes and Laberge. New flood info is highlighted in yellow. New flood response info is highlighted in blue.

As of Sunday morning 4-July, Marsh Lake surpassed the 2007 peak flood level. Laberge surpassed the 2007 peak late on Sunday. Bennett surpassed the peak on Monday and Tagish surpassed the 2007 peak on Tuesday. The Southern Lakes and the Yukon River in Whitehorse are now rising between 1 and 1-1/2"/day. As of yesterday, Laberge began to slow its rate of rise as well. I have added a new page which shows the rise per day over the past week as well as a forecast for the weather.

Flood response:

 *   Southern Lakes Flood Incident Management Team is being led by Mike Smith
 *   The Incident Management Team information line is: This email address is being protected from spambots. You need JavaScript enabled to view it. or 867-332-7084
 *   If you or a neighbour you know needs some help, please let me or the flood team know
 *   Sand and sand bags are now available at 8 locations
 *   1. South McClintock Rd at intersection of Army Beach Connector
 *   2. Boat launch at Nolan Dr
 *   3. Marsh Lake Community Centre in Judas Creek
 *   4. CTFN campground in Tagish
 *   5. Tagish cemetery in Taku subdivision
 *   6. CTFN yard by the airstrip in Carcross
 *   7. Jackfish Bay on Laberge
 *   8. Hootalinqua Fire Hall
 *   The flood team is prioritizing primary residences that are most at risk of flooding
 *   They have retained flood specialists from the prairies and Canadian Armed Forces and Ranger to assist with flood defences
 *   We now have 150 personnel to assist residents and volunteers
 *   We are working to extend landfill hours in support of flood defence activities
 *   7-July, EMO issued an evacuation alert to some residents in Army Beach and South McClintock - this is a precaution so residents prepare in case we hit an unexpected significant wind or rain event which overwhelms flood defences
 *   We are launching a campaign for no boat wake by properties


 *   Southern Lakes winter snow load was more than twice our average
 *   19-March 2021, Yukon Energy (YEC) opened the locks at the Lewes River control structure (roughly 2 months early)
 *   YEC reopened the boat lock and removed the gates completely
 *   YEC removed driftwood from in front of the control structure on Tuesday and they are working to raise and/or completely remove the gates
 *   YEC has dropped elevation of Schwatka by -0.93 m to try to increase flow through Miles Canyon
 *   Some roads are now flooded isolating access to some homes
 *   The current projection of lake level rise is 658m, which is an additional 50 cm / 20" of rise
 *   There remains a lot of uncertainty with all projections and we will need to monitor the rise closely
 *   Dr. Benoit Turcotte (research hydrologist) from Yukon University wrote an article explaining the flood (click here<http://scholar.yukonu.ca/bturcotte/blog/high-water-levels-yukons-southern-lakes?admin_panel=1>)
 *   Flood warning for Southern Lakes was updated on 2-July (click here<https://yukon.ca/sites/yukon.ca/files/env-flood-warning-southern-lakes-july-2-2021.pdf>)
 *   As of 7-July the boil water advisory was expanded for Southern Lakes, Laberge, Kusawa and Takhini River  (<https://yukon.ca/en/news/boil-water-advisory-residents-army-beach-and-south-mcclintock-private-wells-or-underground>click here<https://yukon.ca/en/news/boil-water-advisory-residents-southern-lakes-lake-laberge-kusawa-lake-and-takhini-river-areas>)

The attached graphs show the lake levels of Marsh, Tagish, Laberge and now Bennett over the past 20 years based on Government of Canada hydrometric data. Peak lake levels are typically reached in August. The 2007 flood year is indicated in purple and the average is shown in red. 2021 is shown as the dotted light blue line. I have added the full-supply and low-supply levels in yellow (please note that the Gov Canada hydro data uses relative elevations; I have adjusted the levels by their suggested datum conversions).

If you know of anyone else that would like to receive this update, please let me know. And if you have any questions / information about the flood response, please send them to me or This email address is being protected from spambots. You need JavaScript enabled to view it.

Best,
John

 

Click here for  pdf 2021 07 08 Southern Lake levels (412 KB)

Southern Lake levels: Update 7, 21-June 2021

Hi All,

This is the 7th email update sharing information about the potential flood situation for the Southern Lakes. Yellow highlight indicates where information is new from the last update.

Over the past week lake levels rose about 10 cm a day, rising faster than anytime over the past 20 years, including 2007. As of 21-Jun, Marsh Lake is 80 cm above average and 15 cm above 2007 levels. We still cannot predict how high the waters will get, but I have requested that we hear from EMO this coming week re how and when we will respond. For now here are two links for flood preparation: Yukon<https://yukon.ca/en/take-steps-keep-yourself-and-your-property-safe-floods> & Canada<https://www.canada.ca/en/campaign/flood-ready.html>.


 *   1-May 2021 final snow bulletin came out: (https://yukon.ca/sites/yukon.ca/files/env/snow_bulletin_may_2021_final-en.pdf)
 *   Southern Lakes snow load = 215%
 *   "Water levels in the Southern Lakes are driven by a combination of snowmelt, summer precipitation and glacier melt"
 *   19-March 2021, Yukon Energy (YEC) opened the locks at the Lewes River control structure (roughly 2 months early)
 *   The boat lock on north side of Lewes River control structure open
 *   YEC has dropped elevation of Schwatka by -0.93 m to try to increase flow through Miles Canyon
 *   YEC continues to work with float plane users to find a solution to lower level of Schwatka for this summer
 *   As of 7-May 2021, Marsh Lake level began to increase again
 *   May precipitation for Southern Lakes was up by 29% over average
 *   So far, June precip is above average for Atlin and below average for Whitehorse area
 *   Emergency Measures Organization (EMO) and Water Resources Branch are meeting regularly to discuss risk levels and preparation.
 *   EMO is  reviewing the flood response report from 2008 and I have asked for a report on any outstanding action items.

The attached graphs shows the lake levels of Marsh and Tagish over the past 20 years based on Government of Canada hydrometric data. Peak lake levels are typically reached in August. The 2007 flood year is indicated in a purple; the 2020 year is shown in green and the average is shown in red. 2021 is shown as the dotted light blue line. I have added the full-supply and low-supply levels in yellow (please note that the Gov Canada hydro data uses relative elevations; I have adjusted the levels by their suggested datum conversions).

If you know of anyone else that would like to receive this update, please let me know.

Best,
John

Southern Lake levels: Update 6, 14-June 2021

Hi All,

This is the 6th email update sharing information about the potential flood situation for the Southern Lakes. Yellow highlight indicates where information is new from the last update.

Over the past week lake levels tracked with 2007 levels. To help with visualization, I switched the 2021 plot to light blue to see it better alongside the 2007 plot. Emergency Measures Organization (EMO) and Water Resources Branch are meeting regularly to discuss risk levels and preparation. EMO is  reviewing the flood response report from 2008 and I have asked for a report on any outstanding action items.


 *   1-May 2021 final snow bulletin came out: (https://yukon.ca/sites/yukon.ca/files/env/snow_bulletin_may_2021_final-en.pdf)
 *   Southern Lakes snow load = 215%
 *   "Water levels in the Southern Lakes are driven by a combination of snowmelt, summer precipitation and glacier melt"
 *   19-March 2021, Yukon Energy (YEC) opened the locks at the Lewes River control structure (roughly 2 months early)
 *   The boat lock on north side of Lewes River control structure open
 *   YEC has dropped elevation of Schwatka by -0.93 m to try to increase flow through Miles Canyon
 *   YEC continues to work with float plane users to find a solution to lower level of Schwatka for this summer
 *   As of 7-May 2021, Marsh Lake level began to increase again
 *   May precipitation for Southern Lakes was up by 29% over average
 *   Currently Marsh Lake is 43 cm above average and 8 cm above the 2007 flood levels as of 14-June

The attached graphs shows the lake levels of Marsh and Tagish over the past 20 years based on Government of Canada hydrometric data. Peak lake levels are typically reached in August. The 2007 flood year is indicated in a purple; the 2020 year is shown in green and the average is shown in red. 2021 is shown as the dotted light blue line. I have added the full-supply and low-supply levels in yellow (please note that the Gov Canada hydro data uses relative elevations, so I have adjusted the supply levels to be actual elevations).

Looking back at 2007, through June it was apparent that the lake levels rose very quickly and that we could anticipate a flood. For 2021 and the first two weeks of June, lake levels are currently tracking more closely to 2007 (purple line) than the 20 year average (red line). I have flagged this to the Water Resources Branch, Yukon Energy and the Emergency Measures Office.

If you know of anyone else that would like to receive this update, please let me know.

Best,
John

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