Until this week’s 50-degree temperatures and heavy rain, Maine snowmobilers were enjoying one of their best winters in recent years — and one of their most deadly.

With a fatality reported in Carthage on Friday, seven sledders have died in accidents on state trails and waterways since Dec. 1, and an eighth snowmobiler was killed in an accident on a public roads in Buxton on Feb. 17, according to the Maine Warden Service.

While it’s a miniscule number compared to the estimated 65,000 sleds registered to use Maine trails so far this winter, eight is the most fatalities reported since 2012, when accidents killed 10 people. The modern record for snowmobile deaths, set in 2002, is 16, said Mark Latti, spokesman for the Maine Department of Inland Fisheries and Wildlife, which oversees snowmobile registrations in Maine.

With as much as another month remaining in the snowmobile season, and below-freezing weather expected this weekend, MacDonald and other observers of the $350 million state industry fear the number of fatalities will increase.

The rainfall “has deteriorated trails,” MacDonald said.

The unsafe conditions caused by the rainfall and snowmelt — more exposed stumps, water holes, thin ice and rocks on or near the state’s 14,000 miles of Interconnected Trail System, town and club snowmobile trails — “will be a particular concern,” MacDonald said Thursday.

“It was almost as if this bad weather came a month sooner than it should have,” MacDonald said. “We are kind of nervous about a month earlier than we typically are.”

The most recent fatality occurred on Feb. 27, when a Massachusetts man lost control of his snowmobile at a sharp curve and struck a tree near Landers Farm Road in Eustis, a small town adjoining Bigelow Preserve in Franklin County.

Dennis Picard, 60, of South Chatham, was pronounced dead at the scene. The other fatal crashes happened Jan. 2 in Windham, Jan. 7 in Oakland, Jan. 14 in T1 R9 WELS, Jan. 17 in Buxton, Jan. 18 in Sidney and Feb. 18 in Newport, game wardens said.

From 2010 to this winter, wardens have handled 35 fatalities. The number of accidents involving personal injuries this winter is not yet available, but 645 such accidents were reported from 2010 to 2015, said MacDonald, whose agency monitors snowmobiling and other outdoor activity with 89 wardens, two corporals, 15 sergeants, five lieutenants and three pilots in the field.

From 2010 to 2015, 242 search and rescue missions were conducted to aid lost or injured snowmobilers stuck in the northern Maine woods, where most snowmobiling typically occurs.

With autopsies, toxicology reports or accident investigations incomplete on most of the fatal accidents, exact causes of this year’s deaths are impossible to say at this point, MacDonald said.

But generally, accidents come from a combination of too much speed — Maine law requires riders only to travel at speeds prudent for conditions — sledder unfamiliarity with terrain, snowmobiles that stray onto thin-iced waterways, crashes with obstacles or other snowmobiles, or just plain bad luck. Nighttime accidents are common as visibility dims. Intoxication also often is a factor, said Bob Meyers, executive director of the Maine Snowmobile Association, a largely volunteer organization of 280 snowmobile clubs that maintain the state’s trails.

“It’s awful, but it’s very, very predictable,” Meyers said Thursday of the conditions that usually create accidents. “Nothing good ever happens after midnight.”

“The condition that breeds fatality is in the mind of the guy riding a sled. You can be in the best conditions and still kill yourself,” said Jim Splan, president of the Benedicta Snow Gang, a 90-member snowmobile club in Benedicta, a southern Aroostook County town north of Mount Katahdin.

“If you run ahead of your headlights, if you don’t know where you are, if you are on ice and going too fast, you are out of control. If you are on an unfamiliar trail, you don’t want to be going 60 miles per hour,” Splan said.

Some crashes are legendary. One rider died several years ago when he slammed into an ice shack on a lake at more than 100 mph. It was after midnight and the shack was empty except for a one-gallon can of B&M Original Baked Beans.

The can exploded on impact. Investigators found beans almost 100 yards away.

Splan said he gets disgusted at “the power they put on these sleds now.”

“They are way too fast. You don’t need a trail sled that goes 120 mph,” Splan said. “The chance to overdrive a machine is so much greater when you can go that fast.”

Editors at American Snowmobiler Magazine who tested several of the larger 2016 Yamaha and Arctic Cat snowmobiles, said they consistently reached a peak speed of 116 mph on a frozen lake. Most snow sleds Mainers use are capable of 80 mph or so, Meyers said.

Another factor contributing to accidents, particular to this winter: Unusually heavy traffic on the trails north of Lincoln thanks to riders coming from snow-poor areas like Connecticut, New Hampshire, Vermont, southern Maine and even upstate New York, said Splan, whose club grooms Interconnected Trail System 83 from Benedicta through Sherman, ITS 81 from Sherman to Benedicta and Municipal Trail 70 from Benedicta to Whetstone Falls, in southern Aroostook and northern Penobscot counties.

“Probably this is the heaviest traffic we have seen in the last 10 years, due to the weather and the way the snow set up,” Splan said. “Snowmobile registrations are up all over the state. It’s just been great riding all year, but this year it’s mostly been Lincoln and north where all the snow has been.”

That concentrates a larger number of riders on a smaller number of trails, said Splan, whose club membership has nearly doubled since last year due to the heavier snowfall.

According to the National Weather Service office in Caribou, as of Feb. 28, 90 to 95 inches of snow had fallen on the Caribou-Presque Isle region of northeast Maine, an area widely regarded as among the state’s best for its consistently getting the most snow the earliest in winter.

“From Caribou to Madawaska, it’s Mecca,” Splan said. “They may have a foot of snow [left on the ground] and we might not have any. This year we lucked out. We had it at the end of December. Sometimes we don’t get it until February.”

Other snowmobiling-rich areas, Houlton, Patten and Portage, got 85 to 90 inches through February, while 80 to 85 inches fell from Calais to just north of Lincoln through the Katahdin region northwest to Clayton Lake, Allagash and Fort Kent, according to the weather service

The higher elevation of the Dover-Foxcroft and Greenville areas helped attract 85 or so inches, the weather service states.

This year, northern Maine was rich with snow, said Tim Duda, a meteorologist with the National Weather Service in Caribou, with the high point being when a couple of storms left Caribou and Bangor with some 31 inches on the ground from Feb. 14 to Feb. 20.

But Bangor’s snowpack didn’t last long. As of Friday, Bangor had no appreciable amount of snow on the ground, while Caribou still had 22 inches. East Sangerville had 14 inches, while Millinocket and Fort Kent had good snow depth, with 11 and 12 inches, respectively. Farther south, in Topsfield and Whiting, six inches was reported, Duda said.

The state’s groomers, Meyers said, lengthen the snowmobile season enormously with their careful work creating trails. Groomed trails can have as little as six inches of packed snow and ice and still be passable, but a good trail has a base of two to three feet of snow and ice, plus whatever incidental ice forms or snow falls between grooming runs, Splan said.

That’s why ungroomed trails, and water bodies, are usually the places where the most snowmobiling accidents occur, Splan said.

“I have seen a couple things where people were just driving too fast for conditions,” he said. “If you are driving too fast and you put it into a 4-inch [diameter] birch tree, you’re done. It’ll tear your head off.”

MacDonald wasn’t so sure that ungroomed trails were a leading cause of accidents. He said he believes that most crashes occur on groomed trails. That’s where the most riders go, he said.

It is important, Meyers said, to recognize that the number of injuries and fatalities is miniscule compared to the number of riders on the trails any given winter. State law requires snowmobilers to register their sleds annually, with residents paying $46 per machine and out-of-staters paying $50 to $100 per sled depending on their length of stay in Maine.

The registration provides state officials their best estimate as to the amount of riders out there, Meyers said. By that measure, the eight fatalities are 0.0001 percent of the 65,000 snowmobiles registered so far this winter. Latti said he expects that by the time town offices turn in all this winter’s registrations, the number of sleds should reach 80,000.

The record for Maine registrations is 107,285 sleds for 2002 — perhaps unsurprising, since that also was the year of the record-setting 16 fatalities. The most recent high occurred in 2007, when 101,608 sleds were registered. Only 59,182 sleds were registered and three fatalities reported in the very snow-poor winter of 2015. In 2013 and 2014, 81,522 and 84,224 snowmobiles were registered.

Local clubs see the impact of this winter’s snowfall in increased membership. Splan said his group increased by 37 members this year. But the number of sleds registered and riders on the trails don’t downplay the risks involved, Meyers said.

“With a lot of accidents, you go a foot to the right or the left, you are going to have a good story to tell instead of a fatality,” Meyers said. While most trails are wide enough to accommodate at least two sleds, the difference between an accident and safe passage is often “a matter of degrees.”

Clubs try to limit the likelihood of accidents by making trails as straight as possible, with gentle curves. When sharp turns are unavoidable, club members bank the curves and remove all obstacles within them to improve driver visibility. Clubs mark trails with a dozen different signs warning of looming curves, trail intersections, hazards, stops and trail markers, Splan said.

Club members also will try to pair inexperienced riders with veterans, usually sandwiching the neophytes between the experienced sledders until the beginners learn their way around, Splan said.

But clubs can only do so much to prevent accidents, Meyers said.

“It ultimately comes down to a rider’s personal responsibility,” Meyers said. “You can go very fast, Just because a snowmobile is capable of going that fast, just like your car, it doesn’t mean you have to go that fast.”

“This is always, always about personal responsibility,” he added. “We can’t take care of you when you’re out there in the woods. You’re out there, on your own, and you have to use common sense.”