we like our big friend. >> in groveland the big friend gets the credit.er decades of air drops, some experts doubt aerial firefighting works. >> they are having researchers with trained firefighters going out after the drops occurred to see how effective they are. people are not sure even though they have done this for 20, 30, 40 years. >> researcher bill stuart said we should look at firefighting, tv friendly cnn drops, to see if it is worth it. >> when things are watch, there'll be an updraft of hot air, it will be hard for light material retart and or water to get on to put out the flames. >> it's an expensive fight. aerial assaults cost nearly $11 million, more than 10%. $95 million spent on nine week long firefight. stewart says not only are there questions about the effectiveness of the tankers, but a better investment may be made in more and better equipped boots on the ground. >> maintaining fire safety is the number one priority. there's a question of whether when we invest the next 10 million, how much of that will go to aerial suppression, how

severe thunderstorm warning south of truckee and out here just showers lingering and out toward groveland. showers earlier this evening up in clear lake because of this system. the moisture from this storm or from that tropical storm has moved into the bay area. that's why it's so humid and unconfidentable. -- uncomfortable. we're going to see that humidity shift. it's going to feel a lot different as we move forward. because today's humidity and moisture felt like dallas or houston. big changes coming. we'll let you know what the thunderstorms will end and when the humidity is going to come down. >>> a bridge has collapsed under flooding. right now traffic is being detoured. sudden flooding yesterday eroded the ground underneath the bridge causing it to collapse. two people inside a truck were trapped. the passenger managed to get out. the driver had to be rescued. >>> california governor jerry brown is said to visit the vatican tomorrow where pope francis is hosting mayors and governors from around the world to discuss climate change. among those joining the governor in rome are major e

. >>> i was up in the sierra foothills over the weekend near lake don pedro in groveland and it looks like a little pond now. it's really bad out there. it's so dry. >> i had reports last week on el nino. i hate to talk about that because last year we were so discouraged but it looks promising. will it cure four years of drought? right now looks like it's going to be a pretty hefty el nino but at this time as you head out the door, looking at a drying out period. looking at extremely dry conditions beginning with today. clear skies, look at the bay water. not even a ripple, 50s and 60s. we have a bit of a breeze however in santa rosa, northeast at 12. 64 degrees. numbers today stacking up in the 70s at the beaches. 80s bayside. mid-90s in the inland areas but wait, it gets hotter tuesday and wednesday. extremely dry conditions. high fire danger is an off- shore flow. thursday is very interesting. we could have tropical moisture, heighten our relative humidity, we'll talk more about that at 18 minutes after the hour. >>> roberta, we're still watching the bay bridge toll plaza where eve