Terra only announced this after halting the network, giving their users no opportunity to try to withdraw funds. They have made no announcement about whether or when they intend to bring the network back online, although it seems safe to assume that the enormous loss of confidence in Terra would make any restart short-lived.
Terra blockchain is halted after token crash increases threat of governance attacks
After $LUNA dropped below $0.01, Terra announced that they halted the Terra blockchain. "Terra validators have decided to halt the Terra chain to prevent governance attacks following severe $LUNA inflation and a significantly reduced cost of attack", they wrote on Twitter. This means that no transactions can continue on the Terra chain, and that holders of any tokens based on that chain (including the TerraUSD stablecoin or LUNA) can't do anything with those tokens.