How severe will California's heat wave get near you? Here's a ranking for every neighborhood

San Francisco Chronicle​

2 days ago

This week, state officials launched a new tool that ranks heat wave severity and predicts impacts from sweltering temperatures at the neighborhood scale. The unveiling comes as intense heat is gripping Northern California, with parts of the Bay Area that could face triple-digit temperatures.
Temperatures Friday, according to the new tool — dubbed the California Communities Extreme Heat Scoring System — are classified as 'severe' in places like San Jose, Walnut Creek and Concord. This is the highest heat severity category, on a scale of 0 ('low') to 4 ('severe'). At this level, communities face high risk of heat-related illnesses.

Cooler temperatures are expected in San Francisco. But parts of the city, including the Bayview and South of Market neighborhoods, have a score of 3, corresponding with 'high' heat risk.
Heat risk scores are calculated for individual ZIP codes through analysis of historical climate data, weather forecasts and potential health impacts. The model is based on emergency department visit data during the summer months. Temperature thresholds used for calculating scores differ between ZIP codes.
The California Environmental Protection Agency's Office of Environmental Health Hazard Assessment led the development of the tool.
The National Weather Service provides a HeatRisk tool with similar heat-risk scores for the entire country. But that tool uses county-level data, while CalHeatScore relies on ZIP-code level emergency department data, said Walker Wieland, the program manager for CalHeatScore, during a media briefing Friday.
'We're able to use finer scale health data that really allows us to pinpoint more where those health vulnerabilities are,' Wieland said. The tool also provides socioeconomic and demographic data that highlights populations that may be vulnerable to extreme heat.
'This tool prioritizes those most at risk and helps ensure that no community is left behind,' said Yana Garcia, California's Secretary for Environmental Protection, during the Friday briefing.
Garcia highlighted the correlation between heat and a range of negative health impacts, including increased emergency room visits and hospitalizations for medical issues.
'Not everyone experiences heat in the same way,' Garcia said. 'For example, many Californians don't have access to air conditioning. Some work long hours outdoors. Others are isolated or may face barriers to receiving critical health information.'
A hotter future due to global warming brings additional challenges.
'As climate change drives rising temperatures, and as more frequent and intense heat waves hit communities across California, children in particular, older adults, outdoor workers and those with underlying health issues face the greatest risks,' Garcia said.