We study how the catastrophic 2011 Thailand flood affected Swedish firms that imported from Thailand. Output by the 50th percentile of importers with a higher share of Thai imports in total imports dropped by 8% in 2012. In aggregate, this translates into a 1.08 billion SEK drop in Thai imports for these firms, which translated into over 29.7 billion SEK in lost sales. The magnitude of the amplification effect is striking. The effects of the flood did not go away in spite of the relatively rapid recovery in Thai production, which is consistent with substantial fixed costs in establishing links in supply networks. Another key result is the importance of geographical diversification in a value chain. Our regressions show that firms that import a good from more than one country are almost completely shielded from the flood.