Peak Flows in West Virginia's Streams Are Not Increasing

A couple days ago, Channel 5 (WDTV) from West Virginia published part one of a multi-part series on climate change in the state, which was debunked here at AT.  The station promised part two, and they delivered.

Some claims from the latest installment at Channel 5:

Climate research also suggests that a warming world is leading to shifts in local weather patterns. A recent study found that over the past 50 years, the number of heavy precipitation events in the region has increased by over 70-percent. The rugged terrain here already increases our risk for flooding, and more heavy rain events certainly won't help the problem.

Many may remember the Flood of November 1985. Four to eight inches of rain fell in just 24 hours November 4-5 over southern and eastern West Virginia, causing devastating flooding across the region. 47 people lost their lives and damage was estimated at 570 million dollars across the state...

While the Flood of 1985 can't be tied directly to climate change, a warming world does put us at higher risk locally for more flooding in the future.

As noted in the debunking of part one from this climate change series, “there doesn't appear to be any climate sub-region in West Virginia with a significant increase in the number of days each year having more than two or three inches of precipitation during a 24-hour period since 1970, and especially not during past three decades.”  Thus, the evidence doesn't appear to support a notion that extreme 1-day precipitation events are increasing anywhere in the state.

As for the suggestions that climate change will increase flooding in the state, the USGS maintains a database of streamflow stations throughout West Virginia.  I looked at all 153 sites in the state, and since 1970, not a single hydrometric station in West Virginia has a significant increasing trend in annual peak flows.  Not one.  In contrast, six stations have significant declining trends in peak flows, while the remainder of the stations have no significant trends in either direction.  One must be cautious linking flooding to climate change, anyway, since many non-climate-related factors can influence the severity of flooding (e.g., land use changes, regulation and diversion schemes, etc.).

Overall, the data doesn't suggest that flooding events are becoming more severe in the state, either.  In fact, on the balance of probabilities, peak flows in West Virginia's streams may be declining over time.