Minnesota’s climate is changing. Temperatures are on the rise and extreme precipitation events and associated flooding are becoming more frequent and severe. As the Earth continues to warm, these events are projected to become even more common since a warmer atmosphere is capable of holding more water vapor.
Flooding presents a challenge to fulfilling the Minnesota Department of Transportation’s (MnDOT) mission to, “Plan, build, operate, and maintain a safe, accessible, efficient, and reliable multimodal transportation system..." When roads become inundated, the safety of motorists can be threatened, efficiency is reduced by the need to take detours, and system reliability is compromised.
Recognizing this, MnDOT planners and engineers have long considered minimizing the risk of flash flooding in the siting and design of the state’s roadway network. However, as has been the standard practice worldwide, they have traditionally assumed that future climate conditions will be similar to those recorded in the past. Climate change challenges this assumption and calls for new approaches to understanding vulnerabilities across the highway system and at specific transportation facilities so that appropriate actions, adaptations, can be taken to minimize expanding risks.
This project, one of 19 Federal Highway Administration (FHWA) climate vulnerability pilot studies nationwide looking at the effects of climate hazards on the transportation system, represents a starting point for developing these new approaches. The focus of this pilot study is on flash flooding risks to the highway system. While flooding is not the only threat to the state’s highway system posed by climate change,3 it is likely to be one of the most significant and has already caused extensive disruptions to the transportation system in many areas.
