That means rapid rise. But willkürlich would have been a good German of the day, too. That means arbitrary.
Rapid rise as in: OMG! The Corona incidence rate in Germany is now at 130,2 and rising!
Arbitrary as in
COVID: Germany set to end national state of emergency – Despite a rise in infections, the parties set to form a new government want to end the national state of emergency. But Germany should not yet expect a “freedom day.”
This just goes to show you how arbitrarily the panic buttons are pressed during our brave new COVID era. Just a few months ago, the Germans were losing sleep at night because the COVID incidence rate was threatening to rise over 30. Keep enjoying the show!