The number of fire fatalities in Minnesota this year could climb to 64, after residential fires in Hibbing, Lakeville, Ely and Marshall left seven dead over the long holiday weekend.

If fire is determined to be the cause of death in all four blazes, 2017 will log the highest number of state fire deaths since 2002, said State Fire Marshal Bruce West.

"This year has been a very, very tragic holiday season," said West, whose office is assisting local authorities in the death investigations.

"Unfortunately, we do get spikes at this time of year between Thanksgiving and New Year's."

In a fire that started early Tuesday, Todd Jacob Gillitzer Jr., 9, and Isaiah Adams, 3, died while sleeping over at their grandparents' Hibbing home for Christmas. Their grandparents — retired firefighter Steven Gillitzer, 67, and his wife, Patricia Gillitzer, 63 — also died.

Steven Gillitzer had escaped the home safely, but he went back in to try to save his grandchildren. He saved Jonathan Gillitzer, 8, who was found outside the home.

"He got one child out," West said. "He died rescuing others."

Isaiah Adams was "quick to hug, full of kisses, ready to sing and dance and always curious as to what was behind that next door," wrote a family friend on a fundraising site for the boy.

Friends described Todd Jacob Gillitzer on his fundraising site as "an amazing boy, so full of life with an unforgettable laugh and smile!"

In Lakeville, Jonathan C. White, 29, was killed when his family's home was destroyed in the early morning hours Tuesday. His parents were able to escape the blaze.

Melissa White said in an interview that her last memory of her brother Jonathan came only hours before the fire. After Christmas dinner, she said that he showed her an Irish Celtic knot design that he'd fashioned from rope and planned to use for her upcoming wedding.

"He didn't tell me what he was going to make from that design," she said. "I gave him a hug that night, said 'I love you, and I will see you in a few days.' " She wrote on the family's fundraising page that words were not enough "to express the heartfelt sorrow that we feel for the passing of son and brother."

In Marshall, Kent Sikorski, 49, died in a house fire on Christmas Day, according to an announcement in the local newspaper. And in Ely, an unidentified person died in an apartment fire Wednesday afternoon.

The causes of all four fires are under investigation, West said.

Fire escape plan 'important'

While fire fatalities have dropped from nearly 100 annually in the 1970s, thanks to better fire prevention and public education, holiday rituals such as cooking, lighting candles, using fireplaces and cranking up space heaters can increase the risk of fire.

"This time of the year can be very tragic, very quickly. Our most common cause of structure fire in Minnesota is cooking and heating," West said. "Our number one cause of fire fatalities is careless smoking."

Cooking fires caused 45 percent of all structure fires in 2016, while heating fires — including furnaces, portable space heaters, water heaters and fireplaces — accounted for 10 percent.

West urged residents to check carbon monoxide and smoke detectors and make sure that space heaters are placed 3 feet from bedspreads, curtains and other flammable items.

"Plug that space heater directly into an outlet, no extension cord. Space heaters can be safe if used properly," West said.

He added that cooks shouldn't let visitors, phone calls and texts distract them while at the stove. "If you are doing some holiday cooking, stay in the kitchen," West said.

And he said that every family member should know the fire escape plan for their home. "Practice that escape plan. That fire drill in the home can mean life and death," he said.

The amount of time needed to escape a house fire has dropped from nearly 30 minutes a generation ago to less than four minutes. A video made by the National Institute of Standards and Testing, a division of the U.S. Department of Commerce, illustrates the time difference.

"With today's lightweight construction, the time to escape for a homeowner is significantly less than it was from … older style of homes," West said. "Today you've got three to four minutes. You don't have a lot of time to get out. That's why it's so important to make sure everyone in the home has a fire escape plan. You have to react quickly."

Staff writer Paul Walsh contributed to this report. Shannon Prather • 612-673-4804