According to Official Guinness Records,
Vance Irwin (Canada) performed a 14.6 m (48 ft) ramp jump on water riding his unmodified Polaris 600 snowmobile at Fox Lake Municipal Park, Hanna, Alberta, Canada on 1 July 2002.
In accordance with the rules, both the ramp and landing were in the water (rather than on land).
For a complete list of 2002 records, please visit 2002 Guinness Records in Canada.