Kevin Bittenbender and Kirstie Ennis had done everything that they could do by Sunday night for “the big jump off” of a 47.5-mile Rim-to-Rim-to-Rim hike at Grand Canyon National Park.

Police in Arizona are searching for three family members who were last seen driving together in mid-March after visiting the Grand Canyon ... There were 36 people involved in the crash.

PEOPLE has contacted the Grand Canyon National Park for comment ... Related: Man Who Went Missing During Tropical Storm Debby Found Dead on Submerged Boat, But His Dog Survived “A total of ...