This paper investigates the performance of flash solid state drives (SSDs) as an extension to main memory with a locality-aware algorithm for stencil computations. We propose three different configurations, swap, mmap, and aio, for accessing the flash media, with data structure blocking techniques. Our results indicate that hierarchical blocking optimizations for three tiers, flash SSD, DRAM, and cache, perform satisfactorily to bridge the DRAM-flash latency divide. Using only 32 GiB of DRAM and a flash SSD, with 7-point stencil computations for a 512 GiB problem (16 times that of the DRAM), 87% of the Mflops execution performance achieved with DRAM only was attained.