Setting up the Sandstorm for your Server is the same way as it was for Taki+.
On the new Missioninit you can find these Lines:

//
if ( m_EventManager )
{
// min time between events, max time between events, max number of events at the same time
//m_EventManager.Run( 900, 2700, 1 );
m_EventManager.Run( 900, 2700, 1 );
// registering events and their probability
m_EventManager.RegisterEvent( Sandstorm, 1.0 );
}
//
this means the Sandstorm comes randomly between 900 to 2700 seconds, you can change the time as you wish.
A Gasmask with a good filter protects you from the Storm,
against water and health loss, but not the stamina loss!