ok, I see your point now. All I can say is that AMS has a huge problem with environmentalists. They have achieved through extensive lobbying and spreading of misinformation that the Dutch government has imposed big restrictions on the use of mainly rwy 22 and 27. These are ofcourse the runways that are preferable during strong winds, that are mostly from the southwest hereabouts.This went so far that IFALPA gave AMS a black star for refusing pilots a prefered landing runway under stormy conditions.. .That has changed now; the pilot can refuse a designated rwy and he will get the runway he`s asking for. However in this case he and the company must file a report to the airport authorities.. .I don`t think this is the main reason for the exagerated slots at AMS, though. In my humble opinion ATC in AMS is simply not efficient enough. If you compare their situation to for instance the situation at LHR. Both have 2 runways available under stormy conditions (AMS has 27 for arr and 24 for dep). It seems that at LHR they have a lot more movements though.. .In AMS they always seem to use too much spacing on final.. .Why they use departure slots is a mistery to me. Ever tried to get airborne at AMS at the start of your CTOT window? Lucky if you make it CTOT +5. Even though you`ve called in ready CTOT -20.
As to imposing flight suspensions; I`ve only encountered that once with winds gusting 65 kts. I don`t know why they close down then, but maybe their fairly high tower has to be vacated then? It lasted for about 15 minutes then.. .Ground handling has to be suspended with thunderstorms overhead, due risk of lightning strike, but inbounds are allowed to land.
Hope this helps.