Wildfires on the island of Maui in Hawai`i
5-minute GOES-18 (GOES-West) images of Day Land Cloud Fire RGB, Shortwave Infrared (3.9 µm), Fire Temperature RGB and “Red” Visible (0.64 µm) with an overlay of Fire Power derived product (a component of the GOES Fire Detection and Characterization Algorithm FDCA) (above) showed thermal signatures associated with wildfires on the island of Maui in Hawai`i during the afternoon and evening hours (from 2:01 PM to 11:01 PM, local time) on 08 August 2023 — particularly near Lahaina (the West Maui Fire), where that large wildfire (which began to rapidly intensify around 0121 UTC on 09 August, or 3:21 PM local time on 08 August) caused extensive damage and forced evacuations, with at least 114 fatalities being reported. Near the center of the island, signatures of 2 other wildfires just northwest and northeast of Kula (the South Maui Fire and the Upcountry Fire, respectively) were also evident. Surface reports from nearby METAR sites showed that east-northeasterly wind gusts of 37-39 knots were occurring during that time period (however, a list of Local Storm Reports included wind gusts as high as 67 mph on Maui). The strong winds — along with dry vegetation from ongoing drought conditions across much of Maui County — contributed to the rapid intensification and spread of these wildfires. Additional aspects of the fire environment are discussed in this blog post.
The West Maui Fire in the vicinity of Lahaina exhibited a maximum GOES-18 3.9 µm infrared brightness temperature of 133.24ºC at 0246 UTC (4:46 PM local time on 08 August), along with a maximum Fire Power value of 1885.04 MW (below).
A closer look at GOES-18 Shortwave Infrared images over a longer period of time — from 0001 UTC on 08 August to 0601 UTC on 10 August (below) — revealed that the first of the 3 large Maui wildfires was the Upcountry Fire, whose thermal signature began to rapidly intensify SE of Pukalani around 1101 UTC on 08 August (1:01 AM local time); several hours later, the West Maui Fire thermal signature then began to rapidly intensify near Lahaina around 0121 UTC on 09 August (3:21 PM local time on 08 August), followed by the South Maui Fire whose thermal signature began to rapidly intensify NW of Kula around 0401 UTC on 09 August (6:01 PM local time on 08 August). The GOES-18 thermal signatures of all 3 of these large Maui wildfires had generally diminished by about 0601 UTC on 10 August (8:01 PM local time on 09 August) — although the fires were still not 100% contained at that point.
GOES-18 True Color RGB images (centered on Lahaina) from the CSPP GeoSphere site (below) showed the large and very dense smoke plume from the Lahaina wildfire as it streamed westward across the island of Lanai — along with 2 more narrow smoke plumes from the smaller fires near the center of Maui.
A Suomi-NPP VIIRS Day/Night Band (0.7 µm) image valid at 0036 UTC on 09 August (above) showed that compact Category 4 Hurricane Dora was centered about 800 miles south-southwest of Hawai`i. The arrival of a burst of easterly/northeasterly trade winds across the island chain — partially accelerated by the pressure gradient between a strong anticyclone to the north and Hurricane Dora to the south (for more details, see this Climate Connections summary) — brought a period of anomalously strong lower-tropospheric wind speeds (source), shown below in shades of red to gray (Maui is centered near 21º N latitude, 156º W longitude).
A downslope enhancement (from the 5788-foot summit of Pu`u Kukui) likely played an additional role in creating stronger winds in the vicinity of the Lahaina wildfire — as well as in the area of the 2 wildfires near Kula, with downslope flow from the 10023-foot summit of Haleakala (below).
Accompanying the easterly trade wind burst was the arrival of anomalously low Total Precipitable Water (shades of blue), depicted below.
A 2-day animation of GOES-18 Mid-level Water Vapor (6.9 µm) images from 0001 UTC on 08 August to 0201 UTC on 10 August (below) showed 2 areas exhibiting warm 6.9 µm infrared brightness temperatures (darker shades of orange) — indicative of dry air within the middle troposphere — passing over parts of Hawai`i during that time period.
Plots of rawinsonde data from Hilo and Lihue at 0600 UTC on 09 August (below) showed the presence of very dry air above the trade wind inversion at that time — and a nearly dry adiabatic lapse rate existed from below the base of the inversion (located at an altitude around 5600 ft at Hilo, and 4100 ft at Lihue) to the surface, which would have aided the downward transport of that dry air aloft (enhancing the already-dangerous wildfire environment at the surface). Total Precipitable Water values were 1.15 inches at Hilo (compared to the daily mean value of 1.38 inches) and 1.09 inches at Lihue (compared to the daily mean value of 1.34 inches).
Day Night Band imagery from Suomi NPP (on 7 August) and NOAA-20 (on 9 August) shows the increase in emitted light over western Maui as the fires burned. (Imagery downloaded from the HCC direct broadcast site in Honolulu and cropped. The full-sized toggle is here).
In a sequence of Suomi-NPP VIIRS Day/Night Band (0.7 µm) images from before (08 August), during (09 August) and after (11 August) the Maui wildfires, viewed using RealEarth (below), the intense glow of the West Maui and South Maui/Upcountry Fires was quite prominent in the 09 August image — and a reduction in the intensity of city light emission (due to fire-related power outages) was evident across the Lahaina and West Maui areas in the 11 August image.
Additional aspects of the Maui Fires were discussed in this Satellite Book Club presentation.