Aug. 7, 2013 -- Police in Switzerland are investigating why a hot air balloon carrying members of Malibu, Calif.'s founding family slammed into a power line before plummeting 13 stories to the ground, killing one and injuring three others.
Grant Adamson, 55, died in the crash after he, wife Terry and their two daughters, Megan and Lauren, took off for a sightseeing trip early Tuesday in Château-d'Œx, an area known as the ballooning capitol of the world.
Megan, 20, and Lauren Adamson, 24, had surgery Tuesday and were expected to be fine, while Terry Adamson remained in the ICU with several internal injuries, sources close to the Adamson family told ABC News.
The family had chartered the balloon for a day, according to the Grand Hotel, and the skies were clear. The balloon is run from the hotel although operated by a separate company. The family had been flying for two hours prior to the crash.
The 65-year-old pilot of the balloon was also injured in the accident and taken to the hospital by ambulance.
"We are doing all we can to support and assist the rescue crew and the investigators who are currently trying to determine the exact circumstances under which the accident took place," the hotel said in a statement.
The Adamson family is one of California's most prominent families, helping to develop the wealthy seaside enclave of Malibu in the 1960s. Founding-family scion Grant Adamson was also on the advisory board at Pepperdine University in Malibu, where his wife is a law professor and Megan and Lauren were students.
"Students love [Terry], other faculty members adore her, and Grant was always there humble, kind, friendly. Just a loving couple and family," Pepperdine law profeessor Shelley Saxer told ABC News.
Members of the Adamson family are flying to Switzerland today.
In the United States, despite millions of flights, there have only been 760 recorded hot air balloon accidents since 1964. A total of 67 of them have been fatal.
Veteran NFL receiver Donte Stallworth and his friend were electrocuted in March when their balloon also hit a power line in South Florida.
"[My friend] was in the corner of the basket on fire. The shock felt two or three seconds, but it was the longest two or three seconds of my life," Stallworth told ESPN after the accident.
In February, 19 people were killed when a hot air balloon dropped 1,000 feet to the ground in Egypt.