Attached to the cement block is a rope connected to an electric clock inside a nearby house. When the pallet breaks free of the ice, the rope triggers the clock, which then records the time.
Montpelier's Don Walker has been organizing the guessing game for five years.
Walker and others sell tickets to those who want to guess when the ice will melt. Half of the money from the tickets goes to the person with the closest guess; the other half helps pay for the July 4 fireworks display at Joe's Pond.
So far, Walker, who has owned a home on Joe's Pond for 41 years, has sold 1,000 tickets. Last year organizers sold almost 6,500 tickets, including some to adventurous guessers in California and The Netherlands.
The winner of last year's ice out was Brody Frazier, a 19-month-old baby from East Montpelier.
Brody took home $2,682 for his lucky guess. "Not bad for a toddler in diapers," said Walker.
Last year the ice gave way on April 28. Sometimes it's earlier, but Walker has recorded a melting date as late as May 6.
Tickets for the annual event are on sale throughout Danville, as well as in Barre and Montpelier. "It's a pretty big deal and people get into it," said Walker.
Walker said this might -- or might not -- be another late melting year. "We got a lot of snow early on which insulated the ice from getting too thick," he said.