Contact: Mary Connor, 651-757-2629
St. Paul, Minn.— Though it seems this harsh winter will never end, the big spring thaw has arrived across much of Minnesota. The Minnesota Pollution Control Agency (MPCA) is asking citizens to document one of the most important indicators of spring for our state – the date on which ice disappears from a lake, or lake ice-off.
Lake ice-off is an important milestone for the state each year, particularly for anglers and water enthusiasts who’ve been waiting all winter to launch their crafts — and themselves — into the water again. But lake ice data — the dates of both its appearance and disappearance — could also be an indicator of changing climate trends. The MPCA collects ice-on and ice-off data and makes it available to researchers and the Department of Natural Resources’ State Climatology Office. The more data available to researchers, the better they can track climate trends and their effects on lake health, local wildlife, and citizen lake use. Citizen observers make it possible to maintain records of ice data across the state on a huge numbers of lakes.
The MPCA defines ice-off as the date when ice is essentially gone from the lake. If there is some ice pushed up on shore, but the water is ice-free, the ice is considered to be out. Normally, lakes do not refreeze in the spring once the ice has gone, but if ice does form again after the majority of it has melted, record both dates of ice-on and ice-off for the spring. The most important thing is for the observer to document their own perception of ice-off for the lake in question. For one observer, that might mean the ability to navigate a boat from one point to another; for another, it might mean that a lake is ice-free as far as they can see from their house. It is, however, critical for each observer to use consistent criteria from year to year.
All ice-off dates, any clarifying definitions, and questions can be emailed directly to the MPCA’s ice data collection program at email@example.com.