The purpose of this guideline is to address the significant risk of flooding caused by ice jams, which have historically been the most common cause of flooding in the Northwest Territories (NWT). Recent events continue to highlight their impact, making it essential for municipal, provincial, and territorial agencies, as well as Indigenous communities, to have guidance on producing engineered flood hazard maps.

The scope of the guideline includes covering various ice conditions and processes over the ice-affected period (freeze-up, over-winter, and break-up). It provides best practices for developing flood hazard maps where ice jam flooding is the primary mechanism. While developed for the GNWT, the guideline is also intended to benefit flood mapping practitioners across Canada who deal with ice jam flooding. The guideline does not include guidance on provisional flood mapping of historical flood events.

The target audience for this guideline includes a wide range of flood mapping practitioners and users such as territorial and provincial governments, hydrologists, engineers, consultants, contractors, community planners, emergency responders, academics, researchers, and Indigenous and local communities involved in flood risk management.

The guideline outlines a methodology that includes key steps like data collection, data review and assessment, flood hydrology for design flood frequencies, flood hydraulics (with a focus on the widely used HEC-RAS model) where a model a calibrated and then run for the design flood scenarios, flood mapping for the selected flood scenarios. Climate change considerations are integrated each step of the proposed methodology.

The importance of ice jam flood mapping lies in its role in cold regions like the NWT, where ice jams pose a significant flooding risk. As climate change intensifies, unpredictable weather patterns and river ice conditions make accurate flood mapping critical for preparing communities for future events and adapting to evolving conditions.

The guideline's development was funded in part by Canada through the federal Flood Hazard Identification and Mapping Program (FHIMP).