Q: What is the status of Hurricane Florence?
A: Florence has developed into a powerful storm and is moving toward the coast of the United States. Forecasts expect it to hit somewhere between South and North Carolina on Friday. Based on the current strength, Florence could turn into one of the worst disasters to affect that area in a long time. Florence has weakened from a Category 4 to a Category 2 storm with sustained wind speeds up to 175 km/h (109 mph) due to strong vertical wind shear in the atmosphere. While Florence has weakened below major hurricane intensity, the wind field of the hurricane continues to grow in size. As it reaches shallower waters of the coast it may weaken further since it will not derive much more energy from the ocean. Nevertheless, Florence remains a serious threat.
Q: What is the most damaging aspect of the hurricane?
A: It’s not just the sheer wind force that is potentially damaging. A storm such as Florence brings three devastating ingredients: strong wind, rain deluges and storm surges along the coast. Take Hurricane Harvey, for example: the main damage wasn’t caused by the wind, but by the prolonged rains that led to extreme flooding in and around Houston, Texas.
Current forecasts point to the possibility that something similar may happen when Florence approaches the coast: The steering currents are predicted to collapse for a time, which will slow Florence's advance to a crawl as it nears the coast. This is not good news since it means that all the impacts will be felt over a longer time period.
Q: Can storms such as Florence be linked to climate change?
A: Man-made greenhouse gas emissions have caused a clearly measurable rise in ocean surface temperatures, which is one key factor for hurricanes to develop. However, there are other variables such as wind shear and ocean currents that influence hurricane activity, so it is difficult to link one specific event to climate change. The latest research suggests that we will see hurricanes less frequently in the Atlantic in the future, but when they develop they could be potentially more intense hurricanes. Furthermore, it is likely that climate change will cause more extreme heat waves, droughts and heavy precipitation events.