Municipal Affairs and Environment

Ice Jam Risk Forecast for the Lower Churchill River

Ice jam events on the Lower Churchill River can lead to sudden and large increases in water level, such as those experienced by the Mud Lake community in 2012 and 2017.

Recognizing that this area is vulnerable to the formation of such events, Nalcor Energy retained Hatch Ltd. to explore the development of a simple predictive tool that could possibly be used to provide some warning of ice jam activity and flood risk in the area. This work has identified a noticeable link between ice jam activity and some key meteorological variables in the basin. Using this relationship, a simple tool was developed to track this risk.

Various combinations of parameters were tested, and it was found that ice jam activity appeared to be linked to two key parameters - accumulated snowmelt and rainfall amounts, and the residual thickness of lake ice at the end of the winter. The data suggested that winters with high winter snowpacks/spring rainfall, and larger ice thickness values at the end of April, were more likely to experience ice related flooding.

The ice jam prediction uses 10 day extended weather forecasts which can be subject to change after each weather forecast cycle.

The Forecast Zones are as follows:

  • An Increasing Risk Zone: Shown in light yellow, this zone represents areas of the chart in which ice jam events have not historically occurred, and therefore the risk of their occurrence is considered to be low.
  • A Higher Risk Zone: Shown in orange, this zone represents an area of the chart in which ice jams have formed in the past but there have also been many years in which ice jams have not occurred.
  • A Severe Risk Zone: Shown in red, this zone represents an area of the chart in which ice jams have typically formed. This is likely due to the larger flows created by the high accumulated snowmelt/rainfall, and/or the large estimated end of winter ice thickness on Goose Bay.

Ice Jam Risk Forecast
2018-2019 Season
May 15, 2019
May 14, 2019
May 13, 2019
May 10, 2019
May 9, 2019
May 8, 2019
May 7, 2019
May 6, 2019
May 3, 2019
May 1, 2019
Apr 26, 2019
Apr 24, 2019
Apr 15, 2019
2017-2018 Season
May 18, 2018
May 16, 2018
May 14, 2018
May 11, 2018
May 9, 2018
May 7, 2018
May 4, 2018
May 2, 2018
April 30, 2018


  • The Ice Jam Risk Forecast is based on results obtained from an Ice Jam Forecast Tool prepared by Hatch Ltd. While the forecast tool has been tested against previous events, its ability to forecast future ice jam conditions cannot be confirmed. The model is not intended to predict floods or the severity of a flood should an ice jam occur. The forecast tool relies on weather forecasts which are subject to change.
  • Ice jams may occur as a result of factors which are not incorporated in the model, and floods may occur as a result of conditions other than ice jams.
  • Nalcor Energy and its subsidiaries have made this forecast available for information purposes only, and users of the forecast are urged to assess the risks of a flood from any cause and the potential for personal harm and property damage and to take appropriate steps to mitigate these risks.

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