joining us live to break down the data is caitlin trudeau, a senior research associate at climate central. >> thanks for having me. karina: can you tell us what is a fire weather day? what conditions make that happen? >> when we talk about fire weather days, we really mean those hot, dry, windy days that set the stage for extreme fire behavior. you're seeing these more and more and you can think of them as a red flag days. karina: your research found fir weather days have increased in the u.s. over the last 50 years. what areas have seen the biggest increase? >> the largest increases have been in the southwest, and southeastern california. they are seeing two more additional months of fire weather conditions each year. which is alarming because on average they already see one to two months already of five the -- fire weather conditions. karina: some places are seeing longer time periods of fire weather days? >> it is widespread across the west. karina: can you explain, wh does that mean exactly? >> like i was saying, the southwest, there is an increase of two additional months of fire wea

caitlin trudeau says those areas are seeing two additional months a year with hot, dry, windy conditions. >> they really increase severe fire behavior. they make these fires a lot more ferocious. they can burn faster and longer and hotter. and make it a lot more dangerous for the people fighting the fires and trying to keep them under control. larry: more californians are living in places where weather conditions are increasing fire risk. there are more than 5 million homes in areas that border wildland, up from 3.7 million in 19 90. oakland fire department trying to test a new tool. the department will begin utilizing what they call real-time wildfire sensors in oakland's ghost at risk zones. staffers are installing them in strategic positions. >> air quality sensors will be installed throughout oakland. these sensors will continuously sample air quality. there will be a dashboard showing the status of all the sensors that are online in real time. the vendor will email or text us whenever they are alerting for fire. larry: the new sensors are part of a pilot program expected to last two