To:       Township of Ashfield-Colborne-Wawanosh
Date:    April 18, 2022

Notice of Caution
Heightened Risk of Bluff Erosion 

Record high Lake Huron water levels over the past few years have resulted in significant toe erosion and oversteepening of the shoreline bluffs. In addition, seasonal rainfall and snowmelt have saturated the land and softened the clay till bluffs, making some areas along Lake Huron prone to collapse. These destabilizing conditions will likely lead to an increase in erosion through slope failures, slumping and gully erosion.

Observations from a recent monitoring flight carried out by Maitland Conservation confirmed substantial shoreline erosion evidenced by areas of steepened and slumping bluffs. Although these erosion hazards are always present, Maitland Conservation is cautioning that the shoreline bluffs are likely at the highest risk of collapse since the prominent failures experienced in 1986.

Landowners, the public and municipal employees are encouraged to stay away from top-of-bluff areas in case there has been any movement of the lake bank. In some cases, there may be a delay between erosion at the toe (bottom) of the bluff and subsequent bluff failure.

In addition, beach areas below the bluffs should be avoided. Injury or loss of life could occur if a bluff collapses and beach users are caught in the deposition zone.

For more information contact:
Jeff Winzenried, Flood Forecast Supervisor
jwinzenried@mvca.on.ca
519-357-0890