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MACKENZIE DELTA AND BEAUFORT COAST SPRING BREAKUP NEWSLETTER

Report 2017-013 June 2, 2017 at 19:00 UTC

Friends of Steven Solomon (Dustin Whalen, Paul Fraser, Don Forbes) Geological Survey of Canada, Bedford Institute of Oceanography dustin.whalen@canada.ca, tel: 902-426-0652

Welcome to Breakup 2017 You may also want to check out the Mackenzie-Beaufort Breakup group on Facebook (https://www.facebook.com/groups/1745524288993851/).

This year, in addition to sharing the newsletter to our mailing list of >370 addresses, we are posting the newsletters on the CACCON (Circum-Arctic Coastal Communities KnOwledge Network) website. You can find them at https://www.caccon.org/mackenzie-beaufort-break-up-newsletter/ Funding for our current breakup monitoring activity is from the Climate Change Geoscience Program of the Geological Survey of Canada, Natural Resources Canada. Please let us know if you do not wish to receive these reports (contact info above) and we will take you off the list. For those of you living in the north, we welcome any observations of timing of events, extent of flooding, evidence of breakup, or anything out of the ordinary, and we thank you for all of the feedback received so far. For those interested in conditions further south, we recommend that you contact Angus Pippy (Water Survey of Canada) in order to receive his very useful High Water Report: contact Angus at 867-669-4774 or angus.pippy@ec.gc.ca. Water level data presented in our newsletters are courtesy of Environment Canada (Water Survey of Canada) and are derived from their real-time hydrometric data website at http://www.wateroffice.ec.gc.ca/index_e.html, which we acknowledge with thanks. Particular thanks to colleagues in Inuvik for keeping so many of the delta gauges operating through the difficult breakup season. Weather reports and forecasts are also from Environment Canada (Meteorological Service of Canada) at http://weather.gc.ca. Ice road conditions are from the GNWT Department of Transportation road reports and travel alerts (@GNWT_DOT). Daily MODIS imagery is courtesy of NASA Worldview at https://earthdata.nasa.gov/labs/worldview/.

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Current conditions Clearing skies and warmer temperatures are in the forecast for Inuvik (12°C) and Aklavik (11°C) today. Temperatures are expected to be cooler out on the coast at Tuktoyaktuk (2°C), Sachs Harbour (-1°C), and Paulatuk (0°C) with chances of flurries at each locale. Likewise, Ulukhaktok can expect similar temperatures (2°C) with a chance of flurries or rain showers. On the Mackenzie-Beaufort Breakup Facebook page, Gerry St. Amand reports that he was able to boat safely back to Inuvik on May 31. He reports only a small amount of ‘black’ ice still coming out of east branch at that time. This is after ice blocking the channel forced him to turn back one day earlier. Thanks Gerry for the valuable updates and we are happy to hear you made it safely to town. Water levels Water levels are now in decline throughout the Mackenzie Delta. East Channel at Inuvik (10LC002) is down 31.5 cm over the last 24 hours to 14.2 m at 06:35 MDT (Figure 1). In the outer delta the gauge in Napoiak Channel above Shallow Bay (10MC023) began dropping more rapidly on May 31 and is down 28 cm in the past 24 hours (Figure 2). Unfortunately, the gauges in Middle Channel at Langley Island (10MC010) and Reindeer Channel at Ellice Island (10MC011) are on-line but returning dubious data and the gauges at Kumak Channel and Kuluarpak Channel have been off-line all season, so we have no indication of water levels in the outer delta.

Figure 1. Water level in East Channel at Inuvik (WSC 10LC002) from May 15 (courtesy Water Survey of Canada).

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Figure 2. Water level in Napoiak Channel above Shallow Bay (10MC023) from May 15 (courtesy Water Survey of Canada).

The plot of daily water levels in East Channel at Inuvik shows the timing of this season’s peak was nine days later than last season’s May 20 peak. It’s also significantly later than 2015 when the gauge was offline during the peak which occurred around May 22 (Figure 3).

Figure 3. Daily mean water level in East Channel at Inuvik (10LC002) from May 1 this year (black) with equivalent data from the past 9 years and the record year of 2006 (derived from data courtesy of Water Survey of Canada).

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Satellite imagery The eastern half of Amundsen Gulf was obscured by cloud or fog yesterday (1 June 2017). We can see dark water through it in places, but cannot detect the current landfast ice edge off Ulukhaktok. Ice remains in Darnley Bay, although the outer edge of the landfast near Cape Parry is being eaten away. There is some overflow or flooding visible on the east side of the Hornaday River delta (immediately east of Paulatuk). The former outer half of the landfast ice in Franklin Bay has drifted toward the northwest and remains intact as an 80 km long by >35 km wide drifting ice floe. The west coast of Banks Island is still encased in landfast ice (Figure 4).

Figure 4. NASA Worldview Corrected Reflectance (true colour) from the Terra satellite showing Amundsen Gulf on June 1, 2017.

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In the outer Mackenzie Delta, MODIS imagery (Figure 5), partially cloud-obscured, and Synthetic Aperture Radar (SAR) imagery from the Sentinel 1A satellite (Figure 6) show widespread flooding throughout the outer delta. With much of the delta still flooded, the dark (black) areas on Figure 6 show standing water above the height of the vegetation. This is particularly evident off Reindeer Channel, in the Olivier Islands, on the northern end of Ellice Island and on the island north of Ellice (‘Nellice’). Also, there is flooding on both the north and south ends of Niglintgak Island between Middle Channel and Kumak Channel. The elevated, vegetated levees surrounding some of the flooded areas are apparent as bright (white) areas on the SAR image (Figure 6). At Taglu, the area around Big Lake is also flooded, while Big Lake and other large lakes maintain their ice cover. Also visible on the imagery (Figures 5 and 6) is the expanding open water within and off the delta channel mouths. Middle Channel is now open to its mouth, as is Arvoknar Channel. The channel north of Ellice Island is still partially ice covered, as is the northern outlet or Reindeer Channel. Shallow Bay is now open to beyond the southern outlet of Reindeer Channel.

Figure 5. NASA Worldview Corrected Reflectance (true colour) from the Terra satellite acquired 1 June 2017. Coastline and some channels outlined in blue.

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Figure 6. Sentinel 1A SAR image (HH-HV-HH RGB) acquired 1 June 2017 over the outer Mackenzie Delta. Image shows extensive flooding in the outer delta and expanding melt pools off the channel mouths. Coastline and some channels outlined in yellow. SAR data courtesy of Copernicus Sentinel data 2017.

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In Kittigazuit Bay, MODIS imagery (Figure 7) and Sentinel 1A SAR imagery (Figure 8) from June 1, 2017 show open water at the mouth of East Channel. A narrow finger of open water follows the submerged channel and extends 7.5 km into Kittigazuit Bay toward Hendrickson Island.

Figure 7. NASA Worldview Corrected Reflectance (true colour) from the Terra satellite acquired 1 June 2017 showing open water at the mouth of East Channel and a finger of open water extending into Kittigazuit Bay.

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Figure 8. Sentinel 1A SAR image (HH-HV-HH RGB) acquired 1 June 2017 over Kittigazuit Bay. Image shows expanding open water off the mouth of East Channel. SAR data courtesy of Copernicus Sentinel data 2017.