What has changed 20 years on from Hurricane Katrina? Huge improvements in hurricane forecasting have been made since Katrina hit the city of New Orleans this day 20 years ago. From starting out as a cluster of storm clouds over the Bahamas, Hurricane Katrina went on to become the deadliest (since 1928) and costliest natural disaster recorded in the United States. BBC Darren Bett Lead Weather Presenter 29 Aug 2025 Huge improvements in hurricane forecasting have been made since Katrina hit the city of New Orleans on this day 20 years ago. As part of an Atlantic hurricane season that was the most active in documented history, Katrina took nearly 2,000 lives, destroyed or made uninhabitable an estimated 300,000 homes, and caused more than $100 billion in property damage.From starting out as a cluster of storm clouds over the Bahamas, Hurricane Katrina went on to become the deadliest (since 1928) and costliest natural disaster recorded in the United States.As part of an Atlantic hurricane season that was the most active in documented history, Katrina took nearly 2,000 lives, destroyed or made uninhabitable an estimated 300,000 homes, and caused more than $100 billion in property damage. Although the US National Hurricane Center (NHC) provided an accurate forecast of the storm's track three days in advance, the resulting devastation led to a concerted effort to significantly improve hurricane modelling, prediction, and warning capabilities.
Improved science and technology have increased accuracy.....Technological advances have been the biggest driver of improved forecast accuracy. A combination of satellites, aircraft observations, numerical forecasting models, as well as historical data are used to predict what will happen. Back in 2005 forecasters had access to satellite images every 30 minutes. Today, satellites typically capture imagery every 10 minutes, and during severe weather this can be increased to every 30 seconds. Now more data from satellites and radar can be fed more quickly into more sophisticated models to produce a more detailed forecast. Now In 2005 data from aircraft flown into storms was not being used as part of the modelling. Today unmanned drones are used as part of research to improve hurricane science. Twenty years on scientists have access to more data from the sea. Collected by gliders, floats and drifters, these instruments provide valuable information about the most turbulent region of the hurricane environment, called the boundary layer, where the air meets the ocean. Computer models now also take into account forecast errors for the previous five years. All these, plus advances in computing power and a better understanding of the physics of a hurricane through more data and research, have led to the significant improvements. In 2005 the average tracking error in a 48-hour forecast was 110 nautical miles (200km). Since then, according to the US National Oceanic and Atmospheric Administration (NOAA), the error has reduced by about 50 per cent.
What challenges remain? Forecasting a storm's intensity however remains more challenging. Small changes in atmospheric conditions can have a large impact on whether a storm strengthens or weakens. A 2024 study, external suggested the two main drivers to this uncertainty are changes in wind speed and direction through the atmosphere, known as vertical wind shear, and atmospheric moisture. Vertical wind shear tends to rip storms apart, preventing intensification or even causing a storm to weaken. Moisture in the atmosphere provides the energy to build clouds to great heights and enables storms to "spin up". The most unpredictable storms occur when there is a moderate amount of wind shear and moisture in the atmosphere. Improvements in computing power and new technologies to gather data hope to make these "high uncertainty" storms easier to forecast. Whilst a weather event can now be a forecasting success it is still possible for it to be a communications failure, as demonstrated by Hurricane Sandy in 2012, which hit the east coast of the US,,,,read on https://www.bbc.com/weather/