The courier companies will issue service alerts, whenever there are uncontrollable events that interrupt their transportation networks. Service alerts are due to weather, natural disasters, or other uncontrollable events. Whenever there is a service alert, the courier companies will normally post a list of postal codes or zip codes impacted by the alert. Each service alert is different. The impact on delivery times and further information are posted in the service alert. 

 Courier Service Alerts

Example of a UPS Service Alert