“…most likely primary target as detonating just two of those storehouses could cause an explosion equal to 100,000 tons of TNT…”
Even an absolutely dead center hit on a silo with a missile still in it (ridiculous premise to begin with) would not result in a nuclear event by the warhead on that missile. Yes, the enemy missile would wreak destruction & radiation poisoning but the nuclear material in the silo would not go critical. The US warhead material would likely rupture & add to the general radiation poisoning event.
Although our missiles might get away beforehand, as you say, those detonations would most likely be ground bursts.
The worst of all.