Police say the woman whose vehicle fell 30 feet from the Bath viaduct and landed upside down in the bed of a pickup truck this week likely lost control after her rear-wheel-drive SUV fishtailed in icy conditions and crossed the center line, causing her to over-correct and crash through the guardrail.

Bath police Lt. Robert Savary said Melissa Medina, 37, was driving her 2003 Mercury Mountaineer south at about 35 mph Monday afternoon when she lost control and went off the bridge’s north side.

A mix of snow and rain was falling at the time, and the road was slick, despite having been salted a few minutes earlier.

“Generally speaking, bridges can be very tricky in that regard,” Savary said. “When it’s raining and freezing, they are more susceptible to freezing.”

Medina and her 12-year-old son, Matthew, sustained serious injuries in the wreck. Medina was listed in fair condition at Maine Medical Center on Thursday. Her son’s condition wasn’t available.

The family has declined to release information about Matthew Medina, but a Gofundme page set up to help with the Windham family’s medical expenses describes their injuries.

Melissa and Matthew Medina sustained serious injuries in Monday’s crash and remained in Maine Medical Center on Monday.

Medina sustained a serious gash from the top of her left eye to near her left ear, and doctors found swelling and bleeding in her brain, according to the description. She also suffered a collapsed lung, which has had to be re-inflated; multiple fractured ribs; bruises and other, less severe injuries.

According to the page, Matthew sustained a compression fracture in his spine and a small fracture in his skull, as well as brain swelling that is expected to subside.

“Both are obviously in pain but both are thankful to be alive,” the family members wrote.

In a news release, Medina’s husband, Jason, gave thanks for the public’s support and asked that offers of assistance be directed to an email address set up to help the family: medinashelp@gmail.com.

A full review of the accident, including a detailed reconstruction of what happened, will take several weeks, Savary said.

Medina has three other children, and according to the fundraising Web page, the family is asking for financial help to replace their car, pay for time that Jason Medina is taking off from work and help cover medical expenses.

Roy Ordway, the driver of the pickup truck, was shaken by the impact but miraculously escaped unharmed. The cab of the truck was largely undamaged.

The viaduct was built in 1958, and extensive work to replace the structure is expected to begin this fall at a cost of roughly $15 million.