(Portland, OR)  --  Police aren't sure of the circumstances surrounding a 20-foot-deep hole in which a woman and her dog fell in a yard in Southeast Portland.  The woman was in her back yard in the area of Southeast 38th Avenue and Southeast Clinton Street last night looking for the small dog when she accidentally fell into the large hole.  A passerby heard the woman screaming and called 9-1-1.  Fire crews rescued the woman and her dog after finding them inside the hole, which officials say may have been weather-related or the result of sewer work done in the yard.