Add frost anomaly

monkestation/code/game/objects/effects/anomalies/anomalies_frost.dm

@@ -0,0 +1,52 @@
+#define MIN_REPLACEMENT 2
+#define MAX_REPLACEMENT 7
+#define MAX_RANGE 7
+
+//THE STATION MUST SURVIVE
+/obj/effect/anomaly/frost
+	name = "glacial anomaly"
+	icon_state = "pyroclastic"
+	/// How many seconds between each gas release
+	var/releasedelay = 10
+	aSignal = /obj/item/assembly/signaler/anomaly/frost
+
+/obj/effect/anomaly/frost/anomalyEffect(seconds_per_tick)
+	..()
+
+	if(isspaceturf(src) || !isopenturf(get_turf(src)))
+		return
+
+	var/turf/current_location = get_turf(src)
+	var/list/valid_turfs = list()
+	var/static/list/blacklisted_turfs = typecacheof(list(
+		/turf/closed,
+		/turf/open/space,
+		/turf/open/lava,
+		/turf/open/chasm,
+		/turf/open/floor/plating/asteroid/snow))
+
+	current_location.atmos_spawn_air ("o2=2;freon=1;water_vapor=8;TEMP=180")
+
+	for(var/searched_turfs in circle_view_turfs(src, MAX_RANGE))
+		if(is_type_in_typecache(searched_turfs, blacklisted_turfs))
+			continue
+		else
+			valid_turfs |= searched_turfs
+	for(var/i = 1, i <= rand(MIN_REPLACEMENT, MAX_REPLACEMENT), i++) //Replace 2-7 tiles with snow
+		var/turf/searched_turfs = safepick(valid_turfs)
+		if(searched_turfs)
+			if(istype(searched_turfs, /turf/open/floor/plating))
+				searched_turfs.PlaceOnTop(/turf/open/floor/plating/asteroid/snow)
+			else
+				searched_turfs.ChangeTurf(/turf/open/floor/plating/asteroid/snow)
+
+/obj/effect/anomaly/frost/detonate()
+	//The station holds its breath, waiting for whatever the end will bring.
+	if(isinspace(src) || !isopenturf(get_turf(src)))
+		return
+	var/turf/current_location = get_turf(src)
+	current_location.atmos_spawn_air("water_vapor=200;freon=100;o2=100;TEMP=140") //The cold will be brutal. The water in hydroponics will freeze. We'll have to make do with the food we've stockpiled.
+
+#undef MIN_REPLACEMENT
+#undef MAX_REPLACEMENT
+#undef MAX_RANGE

monkestation/code/modules/events/anomaly/anomaly_frost.dm

@@ -0,0 +1,21 @@
+/datum/round_event_control/anomaly/anomaly_frost
+	name = "Anomaly: Frost"
+	description = "The white frost comes."
+	typepath = /datum/round_event/anomaly/anomaly_frost
+
+	max_occurrences = 5
+	weight = 10
+	min_players = 20
+
+	min_wizard_trigger_potency = 1
+	max_wizard_trigger_potency = 4
+	track = EVENT_TRACK_MODERATE
+	tags = list(TAG_SPOOKY)
+
+/datum/round_event/anomaly/anomaly_frost
+	start_when = ANOMALY_START_HARMFUL_TIME
+	announce_when = ANOMALY_ANNOUNCE_HARMFUL_TIME
+	anomaly_path = /obj/effect/anomaly/frost
+
+/datum/round_event/anomaly/anomaly_frost/announce(fake)
+	priority_announce("Frost Anomaly detected in: [impact_area.name]. Brace for the cold.", "Anomaly Alert", 'monkestation/sound/misc/frost_horn.ogg')