CALS 500

According to Bush and Lemmen (2019) in Canada’s Changing Climate Report, the major drivers of river flooding are extreme precipitation events, snow and ice melt, rain-on-snow events, and ice jams (p. 290). Here, I’d like to focus on the topic of ice jams and, specifically, those that occur in Golden, BC. Ice jams occur when chunks of ice are clumped together, resulting in the blockage of the flow of a river. Under these conditions, the water has nowhere to go and may end up flooding into the surrounding area (NOAA, n.d.). In Golden, the majority of ice jamming events occur between mid-November and mid-January, under early and mid-winter conditions (Matrix Solutions Inc., 2018, p. 4). While flooding from ice jams normally occurs during the spring in Canada, ice jams can also occur in the winter months (Bush & Lemmen, 2019, p. 290), like in Golden. Ice jamming events are important to monitor under changing climatic conditions, whether they occur in winter or in spring.

Ice jams are known to present a significant flood risk to the town of Golden (Matrix Solutions Inc., 2018, p. 3). Historic records show that hazardous ice jams may be increasing in frequency in recent years (Matrix Solutions Inc., 2018, p. 3). Between 2004 and 2018, Golden experienced five ice jamming events which resulted in ponding in low-lying locations adjacent to the Kicking Horse River (Matrix Solutions Inc., 2018, p. 1). This represents an average of one ice jamming event every three years. On the other hand, from the 1880s to 2018 there was an average of one significant ice jamming event every six years (23 winters with significant ice jamming events; Matrix Solutions Inc., 2018, p. 3). The data does not show if there are other periods between the 1880s and 2004 that also experienced a higher than average number of ice jams (Matrix Solutions Inc., 2018), though it is certainly a possibility. 

The impacts of climate change on river ice are complex and not easily predicted (Matrix Solutions Inc., 2018, p. 21). Bush and Lemmen (2019) explained that, across Canada, it is difficult to assess changes to river ice processes that have already occurred due to gaps in data and, where data exists, a lack of assessment of the data (p. 228). They further explained that climate change impacts on river ice properties and ice jamming related-floods are not yet well understood. However, Bush and Lemmen (2019) did note that more mid-winter ice jamming is expected under changing climate conditions (p. 231). Matrix Solutions Inc. (2018) also put forward projected future trends for ice jamming specific to Golden. Of note, ice jamming events are likely to become more severe and may increase in frequency (Matrix Solutions Inc., 2018, p. 21). It is worth noting that these projections regarding ice jams were not associated with a specific climate scenario, such as one of the Representative Concentration Pathways (RCPs) or Shared Socioeconomic Pathways (SSPs). The Matrix Solutions Inc. (2018) report did make use of the Special Report on Emissions Scenarios (SRES), but did not specify a scenario when discussing ice jamming events in particular. In general, the report used the A2 (representing higher emissions) and B1 (representing lower emissions) scenarios (Matrix Solutions Inc, 2018, p. 21). 

Because ice jamming can cause both overtopping of the dike system as well as seepage through the dikes in Golden (Matrix Solutions Inc., 2018, p. 1), I imagine that it could be very difficult to mitigate the risk caused by this potential change in the river ice regime. For example, simply raising the level of the dike system to lower the risk of overtopping will not negate the effects of seepage through the dikes. 

Moser et al. (2017) declared that “the   challenges   of   climate   adaptation   and   resilience   building  are  now an everyday reality for decision makers  across  the  country” (p. 7). They were referring to the United States, but the same can certainly apply in Canada. So how have Golden decision-makers met the reality of adaptation and resilience building when it comes to ice jamming? To start, Golden is gathering more information. The town has recently initiated an ice jam monitoring program (Town of Golden, 2020, p. 26). This program may be able to provide early warning signals of ice jams through the use of remote monitoring equipment on the Kicking Horse River upstream of Golden (Town of Golden, n.d.). Additionally, the data collected will be used to gain a better understanding of the frequency and severity of ice jamming events under a changing climate. The Town of Golden has also updated its floodplain mapping, though it is worth noting that this is not specific to only ice jamming events (Matrix Solutions Inc., 2020). Lastly, in 1995, the Town of Golden set out building bylaws, with regards to at-risk sites on floodplains, that stipulate setback requirements (from rivers and creeks) and building elevation requirements (Town of Golden, 1995). Again, this action is not specific to only ice jamming related floods, but will help preserve homes in the event of floods in general.

Of course, ice jamming is not the only climate change impact that Golden may have to deal with in the future. Other potential impacts include wildfires (and associated poor air quality), extreme heat days, and risks to the town’s water supply (Town of Golden, 2020). Moving forward, the Town of Golden will need to continue to monitor ice jams and other climate impacts, and do the best it can to adapt to a changing climate.

References

Bush, E. and Lemmen, D.S. (Eds.). (2019). Canada’s changing climate report. Environment and Climate Change Canada. https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/energy/Climate-change/pdf/CCCR_FULLREPORT-EN-FINAL.pdf

Matrix Solutions Inc. (2018). Kicking Horse River climate change adaptation: Ice jamming and gravel deposition. The Town of Golden. http://www.golden.ca/getattachment/Departments/Operations-and-Public-Works/5635-522-Ice-and-Climate-R-2018-05-31-final-V1-0.pdf.aspx?lang=en-US#:~:text=Each%20winter%2C%20ice%20jams%20on,danger%20for%20an%20extended%20time.

Matrix Solutions Inc. (2020). Golden flood study and mapping. The Town of Golden. http://www.golden.ca/Document-Library/Floodplain-Management-Kicking-Horse-River/_2020-03-30-GOLDEN-FLOOD-STUDY-AND-MAPPING-final.aspx

Moser, S., Coffee, J., and Seville A. (2017). Rising to the challenge, together: A review and critical assessment of the state of the US climate adaptation field. Kresge Foundation. https://kresge.org/wp-content/uploads/2020/06/rising_to_the_challenge_together_linked_0.pdf

National Oceanic and Atmospheric Administration (n.d.). What is an ice jam? SciJinks. https://scijinks.gov/ice-jams/

Town of Golden (1995). Floodplain management, Bylaw 963. http://www.golden.ca/Document-Library/Floodplain-Management-Kicking-Horse-River/Bylaw-No-963-2c-1995-Floodplain-Management.aspx

Town of Golden. (2020). State of climate adaptation. http://www.cbrdi.ca/sites/default/files/Documents/PDF/Climate%20Adaptation/Report_Golden_StateOfClimateAdaptation_Final_June2020.pdf

Town of Golden. (n.d.). Town of Golden launches Kicking Horse River Ice Monitoring Program. http://www.golden.ca/What-s-New/Town-of-Golden-launches-Kicking-Horse-River-Ice-Mo.aspx