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Dillon’s great ice device

Rotary Club’s ice-melt challenge underway in Summit County.


Rotary Club of Summit County members stand behind the "ice device." Photo courtesy of the Rotary Club of Summit County.


With spring in the air, Summit County residents are turning their attention from the joys of spring skiing to something far more competitive: predicting when the ice will melt on Dillon Reservoir.

Chart provided by the Rotary Club of Summit County

As one of their major fundraisers for the past 32 years, the Rotary Club of Summit County has placed a contraption, known locally as the “ice device,” on the frozen surface of Dillon Reservoir. For $5 per entry, contestants seek to predict the exact date and time that the device falls through the ice.

After the warm, dry winter season and similar conditions predicted for the spring, April is expected to be a popular wager this year. But history won’t be on your side — the device has only plunged into the reservoir in April five times since the event began in 1986.

One thing is certain. With $4,000 going to the winning entry, prognosticators will travel deep into the rabbit hole to predict the outcome. Their complex spreadsheets take into effect past climate, prior years’ winning entries, current conditions, weather forecasts and other variables that remain strictly guarded secrets.

For more information, and to place your prediction, visit

As a rotary partner, Denver Water helps promote the Dillon ice melt contest by hanging promotional banners, on roundabouts on either side of the Dillon Dam Road.