Historical stream flow records and the forecast for 2004 make the current (1999?2004) drought in the southwestern United States the worst one in the past 80 years for portions of the Upper Colorado River Basin (UCRB). For the Colorado River (near Cisco, Utah), the cumulative stream flow deficit (departure from long-term mean) for the current drought is almost 11 km3, or approximately 2 years of average stream flow.Although the current drought is the most significant,based on historical stream flow records, is it the worst ever? Published in Eos, Transactions, American Geophysical Union, volume 85, issue 32, on pages 301 - 308, in 2004.
