Welcome to the GPAA family Gabriel! As many on here will suggest, try contacting one of the local chapters for more information about the area you wish to prospect. They usually have first-hand knowledge of their surrounding areas as well as the latest info on the conditions. 

Looks like the closest chapters to Piru Creek are the Antelope Valley Prospectors - http://www.goldprospector...ome/ChapterId/LANCCA & The Route 66 Gold Miners - http://www.goldprospector...ome/ChapterId/BREACA

Some fellow members on the forum here may also have more information they can help you out with, but try getting in touch with any of those local chapters as soon as you can before you head out this weekend.

Hope this helps and happy prospecting!