diff --git a/src/types/worldStateTypes.ts b/src/types/worldStateTypes.ts
index 723e8875..77bdc3be 100644
--- a/src/types/worldStateTypes.ts
+++ b/src/types/worldStateTypes.ts
@@ -7,7 +7,7 @@ export interface IWorldState {
     Time: number;
     InGameMarket: IInGameMarket;
     Goals: IGoal[];
-    Alerts: IAlert[];
+    Alerts: readonly IAlert[];
     Sorties: ISortie[];
     LiteSorties: ILiteSortie[];
     SyndicateMissions: ISyndicateMissionInfo[];