Downriver Dispatches

The Power of Water

Wahkiakum and Pacific County have had their share of rain and then some with the common result of massive flooding. According to the National Weather service, those who have been residents of coastal areas understand the danger of storm surge damage. Although the tropical storms and hurricanes get named, those who experienced any of these storms are not likely to remember the names of the storms. The January, 2016, east coast blizzard had several feet of snow and the coastal waters pushed massive amounts of water and waves inland off the coast of New Jersey. In May the water levels rose 6.61 feet with the result of major flooding along the north Atlantic coastline. Storm surges are not restricted to just one season in the Pacific Northwest, but can occur any time of the year. The larger storms here are most likely to occur between December and January. Combined with high tides, the storm surge gets amplified.

Most people do not know that fast moving water just above your ankles can knock you off your feet. That happened to my wife one week before we got married. She was crossing a very shallow creek and she was swept away into the swift running Van Duzen River. I was able to get her out of the water safely. Every year there are more deaths due to flooding than from any other storm connected threat. Many deaths occurred in vehicles swept downstream. People have continued to drive around the barriers that warn them the danger of the flooded road. There is no way to know how deep the water is or the condition of the road under the water. Whether someone is driving or walking, when the road is flooded, stop and turn around.

In this area we very rarely encounter flash flooding, but it can happen. The majority of flash flooding is caused by slow moving thunderstorms that move repeatedly over the same area or heavy rains from tropical storms and hurricanes. Flash flooding also occurs when there is a rapid snow melt followed by torrential rain like what occurred in the Pacific Northwest in December of 1964. Flash floods can grow within minutes or hours depending on the intensity as well as the duration of the rain. It also depends on the topography, soil conditions and ground cover. Southwestern Washington is vulnerable because of the clear cutting that allows more water in the run off. Flash flooding moves large boulders, tears out trees, and destroys buildings and bridges in its path while raking through a new channel. Rapidly rising water can reach heights of 30 feet or more. Flash flood-producing rains also can trigger catastrophic mud slides as has been seen many times on State Route 4. Sometimes floating debris can accumulate and restrict the flow of water. This water that is held back by the debris dam can cause flooding upstream and could cause ensuing flash flooding downstream if the impediment should be suddenly released.

The National Oceanic and Atmospheric Administration (NOAA) scientists are considering ways to blend data from radar, satellite, lightning, and rain gauges to improve flash flood monitoring and prediction. This will help overcome significant challenges in estimating precipitation type and amount. The NOAA's Office of Oceanic and Atmospheric Research is diligently working in order to improve warnings and forecasts of floods and flash floods. They hope to see more lives saved and less property destroyed by examination of the meteorological causes of flash flooding and producing flood warning decision making tools. Be safe, go to the beach and enjoy watching the power of water.