Not to sound rhetorical but someone should pose this question to the airport pundits. It is unprecedented for modern airports to cease operations as a result of very reduced visibility. A few questions must be asked regarding airport efficiency. These litmus tests will gauge and quantify the actual efficiency of the airport. With the minimum separation between runways only one of the parallel runways can be used for landings.
Greater separation translates into a reduction in the hourly arrival rate.
This very reason was the impetus behind the construction of the new Denver Airport. Stapleton fell apart during bad weather. Delays ran rampant, planes diverted, and passengers were inconvenienced. Imagine what will happen during consecutive days of marine fog. Airlines design and tailor their schedules for fully functioning airports.