Congressional Research Service Reports on Hurricane Forecasts

In 2017, Puerto Rico was hit by two hurricanes: Irma, which hit a glancing blow, and then direct and devastating landfall by Maria. Hurricane Maria was the most severe natural disaster in Puerto Rico’s history.

The continental U.S. had not been hit directly by a hurricane since 2005, but Texas was bettered by Harvey and Florida by Irma.

The National Hurricane Center (NHC) is part of the National Weather Service (NWS), which is in turn  part of the National Oceanic and Atmospheric Administration (NOAA). The Congressional Research Service recently reported on the NHC hurricane forecasts for 2017 and 2018.

The NHC forecast for 2018 predicts these weather events:

  • 10-16 named storms
  • 5-9 hurricanes
  • 1-4 major hurricanes

Hurricane forecasting

The NHC uses a variety of data sources to predict the track (the geographic path) and the intensity of storms. The Congressional Research Service concludes that tracking has improved over the past five years, but that predicting the intensity of the storms continues to be a challenge.

Historically, it has been difficult even to measure storms, let alone to predict them. Tools used to measure wind speed and rainfall often are blown away by hurricane-strength winds. What’s more, hurricanes — especially fast-developing storms like Maria — are not frequent enough to provide sufficient data to practice with.

There are also factors apart from the intensity of a storm that influence the storm’s effects on places and people. Storm surge, the height of the water, can cause serious flooding even if the hurricane is not at maximum intensity. High levels of rainfall can also cause flooding, even if the winds that determine hurricane strength are not as severe as they could be.

Hurricane Irma features in the CRS report as an example of this phenomenon. Irma didn’t make landfall on Puerto Rico or the US Virgin Islands, but rainfall and storm surge caused significant damage.

At an April, 2018, hearing, the Administrator of NOAA said that 2017’s forecasts “were the best the NHC  ever produced.”

The 2018 hurricane season

From June to November, the annual hurricane season for the Atlantic and Caribbean, there will be an average of 12 tropical storms and 6 hurricanes. The 2018 season has a 44% chance of being average. The prediction is still a bit higher than average.

The National Weather Service recommends putting together an emergency kit and an emergency plan before hurricane season begins. Their website offers downloadable resources to help people living in hurricane-prone areas to prepare.

Hurricane Maria knocked out electricity and water for months. It is not clear that planning ahead or having an emergency kit would have helped people who needed power for dialysis machines. FMEA’s report on the 2017 response  made it clear that FEMA was not well prepared. Puerto Rico may not be prepared for the 2018 season, either.

Electricity has still not been restored to all residents of the Island. Many people still do not have habitable homes. The infrastructure has not been fully repaired. Community organizations are making efforts to create local systems in preparation for the next hurricane.

Read the full report.

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