Assessing the future probable maximum precipitation in Utah under global warming

Probable maximum precipitation (PMP) has been an important criterion for designing hydrological infrastructure and it is likely to change with respect to global warming. To assess the potential risk that hydrological infrastructure in the U.S. state of Utah may encounter under the least mitigated emission scenario of Representative Concentration Pathway 8.5 (RCP8.5), this study identified historical (1950–2005) and future (2006–2100) PMP estimates to quantify the range and degree of change for extreme precipitation. The results show that an averaged RCP8.5 simulated 19.2% (3.43°C) increase in dewpoint temperature will result in a 39% (88.39 mm) increase in 24-h 100-mi² (259 km²) PMP values. It is also found that the rapidly growing metropolitan areas of the state would experience a greater PMP increase (106.43 mm) than that in the state's National Parks and forested areas (93.98 mm). This discovery indicates a vulnerability that could affect both hydrological and metropolitan infrastructure. The planning of the state's infrastructure needs to consider the changing PMP under global warming.