A frightening collapse of the Yemeni riyal

The Yemeni riyal recorded a frightening collapse in trading today, Tuesday, May 14, against foreign currencies.
The prices were as follows:
Exchange rates in Aden:
-US Dollar:
Purchase: 1694
Sale: 1704
-Saudi Riyal:
Purchase:446.5
Sale: 447.5
Exchange rates in Sanaa:
-US Dollar:
Purchase: 525
Sale: 528
-Saudi Riyal:
Purchase: 139
Sale: 140