A Surface Observation Based Climatology of Diablo-Like Winds in California’s Wine Country and Western Sierra Nevada

Abstract

Diablo winds are dry and gusty north-northeasterly downslope windstorms that affect the San Francisco Bay Area in Northern California. On the evening of 8 October 2017, Diablo winds contributed to the ignitions and rapid spread of the "Northern California firestorm", including the Tubbs Fire, which burned 2800 homes in Santa Rosa, resulting in 22 fatalities and $1.2 B USD in damages. We analyzed 18 years of data from a network of surface meteorological stations and showed that Diablo winds tend to occur overnight through early morning in fall, winter and spring. In addition to the area north of the San Francisco Bay Area, conditions similar to Diablo winds commonly occur in the western Sierra Nevada. Both of these areas are characterized by high wind speeds and low relative humidity, but they neither tend to be warmer than climatology nor have a higher gust factor, or ratio of wind gusts to mean wind speeds, than climatology.

The Synoptic and Mesoscale Evolution Accompanying the 2018 Camp Fire of Northern California

“…The Camp Fire event of 8 November 2018 was associated with dry, northeasterly winds recently has frequently been called a Diablo wind, with its general characteristics described in a number of papers (Monteverdi 1973, Bowers 2018, Nauslar et al, 2018, Smith et al 2018Mass andOvens 2019, McClung andMass, 2020). Central Valley.…”

Santa Ana Winds of Southern California Impact PM2.5With and Without Smoke From Wildfires

“…Simple statistical approaches quantifying relationships between wind and PM 2.5 in the presence and absence of pollution sources (e.g., wildfire), could be particularly useful to help in forecasting and identifying wildfire‐generated PM 2.5 . The same approach used here could be extended to other downslope wind systems in California and elsewhere, which also spread wildfires, for example, Diablo winds of Northern California (Mass & Ovens, ; Smith et al, ). Specific wind systems, and wind data in general, could also serve as the link between wildfire smoke PM 2.5 and wildfire risk in climate change scenarios (Westerling, ).…”

Climatology of diablo winds in Northern California and their relationships with large-scale climate variabilities

“…DWs often occur in and affect two areas of Northern California, namely the SFBA and the western slopes of the Sierra Nevada mountains (Brewer and Clements 2020;Smith et al 2018). The Tunnel Fire, the Tubbs Fire, the Nuns Fire, the Atlas Fire, and the Redwood Valley Fire each occurred in SFBA, while the Camp Fire occurred in the western Sierra Nevada Mountains.…”

“…We identify DW events in a similar fashion as did Smith et al (2018), but with adjustments to incorporate the reanalysis data that will be used for analysis. The DW events are identified independently for each dataset.…”

“…Among the top 20 most destructive wildfires in California history, six of them-the Camp Fire (2018), the Tubbs Fire (2017), the Tunnel Fire (1991), the Nuns Fire (2017), the Atlas Fire (2017), and the Redwood Valley Fire (2017)-have been linked to the occurrences of Diablo Winds (DWs). DWs play two important roles in wildfire activities: (1) causing ignition by pulling down power lines or poles, and (2) rapidly spreading fires and increasing the fire size (Mass and Ovens 2019;Monteverdi 1973;Pagni 1993;Smith et al 2018). As a precautionary measure, several DW events in 2019 prompted the Pacific Gas and Electric Company to shut-off power in several areas of the San Francisco Bay area (SFBA), affecting the daily lives of many residents.…”