More than a year ago, West Maui was hit by a powerful windstorm that slammed into its slopes, sparking a wildfire that destroyed the historic town of Lahaina.
Lahaina after the fire August 8-9, 2023
A terrible tragedy took the lives of about 100 people and caused about $4 billion in damage.
Hawaiian Electric, local authorities and others have taken a number of steps to prevent a recurrence of this tragedy. Unfortunately, for the reasons outlined below, I am concerned that there are gaps in their efforts that could lead to a repeat of the terrible disaster of August 2023.
Meteorological Check of the Lahaina Event
I do a lot of research on the meteorology of western US wildfires, and in particular wildfires associated with downhill wind events, which characterized the 2023 Maui wildfires. I received a grant from the National Science Foundation to study the meteorology and predictability of the Lahaina event, and after some intensive work with research meteorologist David Ovens, published an article on this topic.
The paper makes several key findings:
1. The wildfire was linked to a powerful storm that hit the slope, downing power lines and sparking a fire.
2. This event can be predicted about a week in advance using high-resolution forecasting models.
3. The observation network on Maui and the remaining islands is very poor.
4. There were multiple levels of failure by Hawaiian Electric and public agencies. Furthermore, the National Weather Service never highlighted a specific threat to Lahaina even though their high-resolution model (HRRR) clearly predicted high winds (see below)
NWS HRRR Model
Hawaiian Electric’s efforts to deal with the threat
In recent months, Hawaiian Electric has announced its response to the wildfire threat.
First, they will install dozens of new weather stations across the island, especially in areas with limited visibility. For example, there are now observations near Lahaina where there were none before (see current map below). This is good. But there are still huge gaps in the observing network. Furthermore, surface observations tell you what is happening NOW, not what will happen in the future. And to save lives and property, forecasting is critical.
Finally, there is a lack of airborne observations, which are crucial for forecasting (more on this later).
Real-time surface weather observations in Maui
Second, Hawaiian Electric plans to consolidate and modernize its distribution network, Most of them are outdated and do not meet modern standards for durability in high winds. Praiseworthy and a high priority, but will take years to complete.
Third, Hawaiian Electric plans to begin implementing Public Safety Power Shutoffs (PSPS) when threatening conditions are predicted, not unlike what California utilities have done. This is how they address a deficient power distribution grid that is surrounded by many combustible fuels.
Unfortunately, their PSPS plan has many weaknesses.
According to Hawaiian Electric documents, their decision to activate PSPS will first depend on observations (identifying persistent drought conditions, wind gusts of 45 mph or greater, relative humidity below 45%). That’s a good start, But the response to observations is not good enough. Winds can increase suddenly. Residents, businesses and others need more time to prepare.
Hawaiian Electric announced it will use public forecasts from the National Weather Service (NWS), but that is not gEnough, something highlighted by the relatively poor performance of NWS predictions during the Lahaina wildfire. In that event, the NWS did not highlight a major threat to Lahaina. Instead, the NWS issued a general summary red flag warning for the lee side of all Hawaiian Islands. Not good enough.
Hawaiian Electric needs to use high-resolution numerical model forecasts to make decisions, including declaring PSPS.
There are several different ways Hawaiian Electric can ensure such model predictions:
1. Run your own models, which is what California utilities (e.g. PGE) are doing.
2. Use the NOAA/NWS HRRR-Hawaii model, which is run regularly in “test” mode. This is completely silly, by the way…NOAA/NWS needs a high-resolution, hardened model work model for hawaii.
3. Hawaiian Electric should use high-resolution regional weather forecasts produced by the University of Hawaii Manoa.
Hawaiian Electric also needs to have a team of meteorologists constantly monitoring both observations and high resolution model forecasts. I don’t think they have any models at this time.
They should also work with the USDA Forest Service to provide Hawaii with important wildfire weather diagnostics that the rest of the United States is also using, such as the valuable HOT-DRY WIND diagnostic.
A better view from above Hawaii
To predict and diagnose downdraft storms…the primary driver of Hawaii’s catastrophic wildfires, one must know the structure of the air approaching the islands through the depths of the lower atmosphere. Currently, Hawaii only has such information twice a day at two radiosonde sites: Hilo and Lihue, where instrumented weather balloons are launched twice a day (see stars on map). Not good enough.
Hawaiian Electric, the State of Hawaii, and the Federal Government need more aerial observations of the islands. One approach would be to add another radiosonde unit, with more frequent vertical depth measurements. Or Hawaii could secure some vertical forming machineremote atmospheric sensing devices (see below). The West Coast has many of these, why not Hawaii?
We Can Prevent the Wildfires in Hawaii
Last year’s disaster in Lahaina was preventable. Weather modeling and observational capabilities have improved so much that we can predict events like this with great clarity and skill, allowing for effective responses to minimize loss of life and damage. Hawaiian Electric and Hawaiian government agencies must use these tools to prevent another tragedy.
