A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in Sandra Patnaude, 59, of Wonder Lake, (pictured) being killed and two of her family members being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo – Left: Provided; Photo – Right: Submitted to Lake and McHenry County Scanner

A family friend has identified a woman suspected to have died after an explosion and fire leveled her home in Wonder Lake and left her husband and son both seriously injured Sunday evening.

The Wonder Lake Fire Protection District and McHenry County Sheriff’s Office responded around 7:50 p.m. Sunday to the 7400 block of Birch Drive in Wonder Lake for a report of a structure fire and house explosion.

Wonder Lake Fire Chief Matt Yegge said fire crews arrived on the scene in under two minutes.

They encountered an active house fire with significant damage and multiple injured victims.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo Submitted to Lake and McHenry County Scanner

Firefighters immediately initiated both fire suppression operations and emergency medical care for the injured, Yegge said.

The Mutual Aid Box Alarm System (MABAS) was activated to the box alarm to bring additional fire and EMS resources to the scene due to the severity of the incident.

Sheriff’s deputies first on the scene reported two elderly residents were unaccounted for, according to police radio traffic.

Deputies rescued one of them but reported another was still trapped.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Joe Shuman/J. Shuman Photography (2026)

Firefighters located an adult female victim dead at the scene, Yegge said, adding that there were two other victims still alive.

McHenry County Coroner Dr. Michael Rein on Monday said his office has not positively identified the victim yet due to the severity of the burns and further testing will be needed.

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Jason Cynowa, a resident of Wonder Lake since 1977, identified the woman suspected to have died as Sandra Patnaude, 59, of Wonder Lake.

The two surviving victims were a 76-year-old man and a 28-year-old man, the sheriff’s office said.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo Submitted to Lake and McHenry County Scanner

Cynowa told Lake and McHenry County Scanner that the older man was the husband of Sandra Patnaude and the younger man was the couple’s son.

Cynowa called the incident the “most tragic thing” and a “horrific accident.”

“I have known these people for over 30 years and they are very good people and have been members of our community for probably as long as my family has been here,” he said.

Cynowa said the family are customers of his. He has created a GoFundMe account to help the family going forward and it has raised almost $5,000 as of Tuesday.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Thomas Koch

“My customers seem to always get close enough to me like friends and family. Dean works in our area almost every day and so do I. Just very, very good-hearted people,” he said.

A LifeNet medical helicopter was requested to land nearby at Wonder Lake Fire Station #1.

An ambulance transported the 28-year-old male victim to the landing zone and transferred them to the flight crew.

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The helicopter flew the man to Loyola University Medical Center in Maywood, which has a specialized burn center, in critical condition, Yegge said.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Joe Shuman/J. Shuman Photography (2026)

The 76-year-old man was initially transported by ambulance to Northwestern Medicine Hospital in McHenry. Sheriff’s officials said he suffered serious injuries.

A LifeNet medical helicopter later transferred him from Northwestern Medicine Hospital to Loyola University Medical Center for further treatment.

An autopsy was performed on the female victim and toxicology testing is pending, Rein said.

The explosion and subsequent fire also caused damage to two neighboring houses.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Joe Shuman/J. Shuman Photography (2026)

Firefighters worked to contain the fire and prevent further extension, Yegge said.

The house that exploded was left completely leveled and destroyed, with large pieces of the home thrown around the area. The home’s detached garage remained standing.

Thomas Koch, who lives a half-mile away from the scene, told Lake and McHenry County Scanner that he heard the explosion, which sounded like a “massive boom” that shook the area.

“Shortly afterward, I could hear nonstop sirens as fire trucks and ambulances continued heading toward the scene. Seeing the large flames and thick smoke from that distance was honestly unbelievable,” he said.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photos Submitted to Lake and McHenry County Scanner

Numerous other residents in Wonder Lake also reported hearing the explosion. “It shook our whole house 2.5 blocks away and all the neighbors felt it too,” one resident said.

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Other residents who live in the area said they thought a vehicle had struck their house based on how loud the explosion was.

“We are two blocks away and it was raining paper on fire and a whole bunch of ashes. A bunch of mortgage papers,” another resident said.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Thomas Koch

Yegge said he could not confirm whether there was more than one explosion.

“The Wonder Lake Fire Protection District extends its deepest condolences to all those affected by this tragic event. We would also like to express our sincere appreciation to our mutual aid partners who responded and provided critical assistance,” the fire chief said.

Investigators from MABAS Division 5, the Office of the Illinois State Fire Marshal’s Office and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are jointly conducting an investigation.

A house was left completely leveled and two additional houses were damaged during an explosion that caused a fire that resulted in a woman being killed and two others being seriously injured in the 7400 block of Birch Drive in Wonder Lake Sunday evening. | Photo: Joe Shuman/J. Shuman Photography (2026)

Firefighters remained on the scene until 3 a.m. Monday and the sheriff’s office remained holding the scene.

Yegge said he has been in the fire service for 30 years and has only seen a few incidents of this magnitude. “Very rare, very rare for you to see fire scenes like this.”

Investigators returned to the site on Monday morning to continue the investigation. Yegge said there was no preliminary cause yet.