Bitcoin and other cryptocurrencies have crashed dramatically as panic and margin calls have struck the market.Mining giant Riot Blockchain has seen its value nearly cut in half as it is unlikely to mine profitably at current Bitcoin prices.The global energy shortage leads to higher electricity costs in the U.S - a vital issue for Riot Blockchain, which currently uses as much power as ~225K homes.Competition has surged as high Bitcoin prices have caused many miners to pursue aggressive expansion plans simultaneously, likely causing the network hash rate to swell into 2022.Bitcoin may continue to crash and pull RIOT lower as margin calls combined with panic are a recipe for cascading declines.