Denver’s Carol Rymer Davis and her fellow balloon pilot, Richard Abruzzo, were declared missing Wednesday, as thunderstorms rolled over the Adriatic Sea during the Gordon Bennett Cup, a contest to see which gas balloon can fly the farthest over participating European countries. A statement from cup officials notes that although the Davis-Abruzzo hydrogen-lifted balloon is equipped with a satellite phone, VHF radios, radar transponder, and two mobile phones, “it has not been possible to make contact on any of these.”

Officials with Italy’s coastguard said boats would search for the couple through the night and that aircraft would rejoin them when the sun rose, writes BBC News. Massimo Maccheroni of the Italian coastguard says the search is focused 13 miles off Cap Gargano in the Puglia area.

Davis, a radiologist in Denver, began ballooning in 1972 and is set to be inducted into the Colorado Aviation Hall of Fame later this year, reports 9News.

New Mexico Governor Bill Richardson has requested federal assistance to bring U.S. military resources to the aid of the Italian rescuers. Abruzzo is from Albuquerque, and his father, the late Ben Abruzzo, was one of the first balloonists to cross the Atlantic in the Double Eagle II, according to New Mexico Business Weekly. Davis and Abruzzo won the cup in 2004.