It's likely to be only a temporary closure of the Chinese factory. SK Hynix produces half of their DRAM chips at the Wuxi plant. Whether this will lead to DRAM price increase, I doubt. Wait and see, and wait for at least two weeks.
I think it was not a massive fire at all. The smoke was massive, and surely it caused a lot of air pollution in the city. Some of the reports on the web says only one "diffusion" equipment at the C2 line is lost. The entire plant stopped instantly, but that's mostly standard procedure.
Hynix has only about 10% of the world's NAND flash chip marketshare. The Wuxi plant mostly makes DRAM.