AUGUSTA — A year ago Monday, four snowmobile riders died on Rangeley Lake after they drove their sleds into open water.

The Maine Warden Service and Maine Snowmobile Association are hoping a public service announcement unveiled Monday prods snowmobilers into using common sense in order to avoid similar tragedies.

Thanks to heavy snowfall and cold temperatures, this winter’s snowmobile season is already shaping up to be spectacular, the head of the association said Monday at a press conference.

But busier snowmobile seasons can lead to more crashes, sometimes fatal, for the riders.

The Maine Department of Inland Fisheries and Wildlife, which oversees the warden service, and the snowmobile association hope the public service announcement, which will air on the state’s television stations in the coming days, will keep those numbers down this year.

Corp. John MacDonald of the Maine Warden Service said the number of crashes have trended down over the years, but it tends to fluctuate with the conditions.

Almost 40 snowmobilers died in crashes over the last six years, according to the warden service. There were 186 crashes last year, including 119 that caused personal injury, and five deaths.

Four of those deaths occurred the same night on Rangeley Lake.

Two parties of snowmobilers, a mother and son, and three men in their 40s, fell into open water in the Franklin County lake Dec. 30 last year.

Dawn Newell, 45, of Yarmouth, died, but her 16-year-old son managed to jump from his snowmobile onto solid ice before his machine sank. Newell’s body was found the next day.

The bodies of the others, Glenn Henderson, 43, of Sabattus, Ken Henderson, 40, of China, and John Spencer, 41, of Litchfield, weren’t recovered by wardens until May.

The public service announcement focuses on the dangers of driving snowmobiles after drinking alcohol — along with speed, a common contributing factor to crashes, MacDonald said.

The ad shows a group of jovial men around a table drinking before heading out on their snowmobiles. It then cuts to members of the warden service greeting the wife and young daughter of one of the riders at their home to deliver the bad news.

MacDonald said it’s especially hard to see children or others who have done nothing wrong hurt in crashes. Other times, he said, it’s clear the victims could have avoided the tragedy by making better choices.

“They all stick with you, especially the bad ones,” he said.

MacDonald said the spot is also aimed at family members of snowmobilers, so they’ll encourage their husbands or wives or children to be safe while riding.

Besides speed and alcohol, other common contributing factors to crashes include driving in inclement weather and not being familiar with the area, particularly on bodies of water, MacDonald said.

There isn’t a speed limit for snowmobiling in Maine, but state law requires snowmobilers to not exceed a reasonable and prudent speed. It’s also illegal to operate a recreational vehicle under the influence of drugs or alcohol. The legal limit is the same for driving a car — a blood alcohol level of .08 percent.

MacDonald advised riders to make a trip plan to alert others where and when they’ll be out. He said letting friends know of plans helps rescue efforts if something goes wrong. Otherwise, wardens won’t know where to search, delaying a chance of rescue.

The warden service conducted 39 search and rescue missions last year, MacDonald said, ranging from brief missions to the almost five month search for the snowmobilers in Rangeley Lake.

Bob Meyers, executive director of the Maine Snowmobile Association, recommends checking with trustworthy people in the area before snowmobiling on bodies of water that might not be frozen.

“If you don’t know, don’t go,” he said.

The Maine Warden Service is the law enforcement agency that enforces snowmobiling laws. MacDonald said since the wardens can’t patrol all the time, snowmobilers should work together to follow laws and practice safe riding.

“Somebody watching this, it will happen to them,” MacDonald said of the public service ad, “but we hope it doesn’t.”

Paul Koenig — 207-621-5663 pkoenig@centralmaine.com Twitter: @paul_koenig