MACKENZIE DELTA AND BEAUFORT COAST SPRING BREAKUP NEWSLETTER

Transcription

1 MACKENZIE DELTA AND BEAUFORT COAST SPRING BREAKUP NEWSLETTER Report Tuesday June 5, 2018 Friends of Steven Solomon (Dustin Whalen, Paul Fraser, Don Forbes) Geological Survey of Canada, Bedford Institute of Oceanography tel: Welcome to Breakup 2018 Welcome to the 2018 Mackenzie and Beaufort breakup season We are now into our 13th season of the breakup newsletter, which was started by Steve Solomon in This year is the third breakup season for the Mackenzie-Beaufort Breakup group on Facebook Over time we hope this forum hosted in the ISR will take over as the main place to share observations and experience during breakup in the Delta and the coastal communities of the region. Funding for our current breakup monitoring activity is from the Climate Change Geoscience Program of the Geological Survey of Canada, Natural Resources Canada. Again this year we are posting the newsletters on the CACCON website: 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 photos, observations of timing of events, or anything out of the ordinary, and we thank you for all of the feedback received so far. Water-level data are courtesy of Environment and Climate Change Canada [ECCC] (Water Survey of Canada) and derived from the real-time hydrometric data website at which we acknowledge with thanks. Weather forecasts are also courtesy ECCC (Meteorological Service of Canada) at Current Conditions The weather in the delta continues as a mix of sun and cloud with highs today of 17 C in Inuvik, 10 C in Aklavik, 18 C in Fort McPherson, and 5 C in Tuktoyaktuk. Paulatuk is mainly sunny with a high of 6 C and light wind. Ulukhaktok is mostly cloudy with a forecast high of 1 C. At 14:00 MDT it was 2 C with wind east at 42 km/h gusting to 52. Sachs Harbour is warming up, partly cloudy with a high of 4 C, and wind light.

2 Water levels Water levels throughout the delta are dropping at a near linear rate, as ice-related flow constraints through the delta and at the delta front appear to be largely relieved. The daily mean water level plots for Peel Channel above Aklavik (Figure 1) and Reindeer Channel at Ellice Island (Figure 2) tell the story for the central and outer delta, respectively. Figure 1. Daily mean water levels (provisional) in Peel Channel at Aklavik (10MC003) in selected years since 2006 and 2018 (black). Figure 2. Daily mean water levels in Reindeer Channel at Ellice Island (10MC011) for the past decade. 2

3 Satellite Imagery Satellite imagery yesterday gave a clear view over the entire region. On the Yukon coast, fracturing of the landfast ice in Mackenzie Bay, which began overnight on June 3, continued yesterday, with more ice lost off Babbage Bight (Figure 3). The width of the landfast ice off Kay Point is now down to 7 km. We are now seeing very distinct turbid water coming from the Mackenzie, the first clear view of the plume beyond the landfast ice this year, extending west almost to Kay Point. Along the coast, water is confined behind the barrier at Nunaluk Spit at the mouths of the Malcolm and Firth Rivers. Flooding continues in the Babbage Delta but water appears to be flowing under the ice in Phillips Bay. There is still extensive snow cover on the coastal plain west of the Babbage, but much of the latter s drainage basin including the coastal plain has greatly reduced snow cover. Figure 3. NASA Worldview Corrected Reflectance from the Terra satellite for 4 June 2018, showing the Yukon coast and Mackenzie Bay. Most channels in the delta now look mostly free of ice, except in the Taglu area (northeast, where winter still seems to hold sway), in the unnamed channel east of Ellice Island, and in part of outer Reindeer Channel (Figure 4). Overbank flooding seems to be receding as the water level continues to drop in the delta channels (Figure 2). We see extended ice overflow from Kumak Channel on the east side of Garry Island for the first time this year 3

4 and more water around Kendall Island. Open water is expanding along the east side of Shallow Bay and melt pools are beginning to expand from areas of bottomfast ice flooding along the delta front. Flow from East Channel into Kittigazuit Bay is expanding along the axis of the under-ice channel running out toward Hendrickson Island, but breakup of Kugmallit Bay is only just beginning. Unflooded areas of the delta, including the Taglu delta plain and the outer parts of Langley and Ellice islands remain snow-covered, as does much of Richards Island. The highest surface sediment concentration in the Mackenzie plume is directed to the NNW beyond the landfast ice north of Garry Island and we can also see plume water off the Yukon coast to the west (Figure 3 and left side of Figure 4). Figure 4. NASA Worldview Corrected Reflectance from the Terra satellite for 4 June 2018, showing the northern Mackenzie Delta, Kugmallit Bay, and western Tuktoyaktuk Peninsula. Note the turbid Mackenzie River plume now extending north beyond the landfast ice, and the large 20x40 km floe broken away from the ice in Mackenzie Bay. In Amundsen Gulf (Figure 5), Franklin Bay, Darnley Bay, Dolphin and Union Strait, western embayments on Victoria Island, De Salis Bay and northern Thesiger Bay are still encased in landfast ice, as it the west coast of Banks and Prince of Wales Strait between Banks and Victoria islands. The central part of the Gulf is now largely ice-free, with most loose pack concentrated in the north against the Banks Island coast. Open water extends to the coast at Nelson Head, east of De Salis Bay, north of Ulukhaktok, along close to 100 km of mainland coast east of Darnley Bay, and south of Cape Bathurst (Figure 5). We can see evidence of snowmelt on the south-facing slopes of southern Banks east of Sachs Harbour, and extensive snowmelt on the mainland south of Paulatuk. 4

5 Figure 5. NASA Worldview Corrected Reflectance from the Terra satellite for 4 June 2018, showing the northern Amundsen Gulf with landfast ice still present at Sachs Harbour, Ulukhaktok, and Paulatuk. Focusing more closely on the area around Paulatuk, the area of blue ice has expanded rapidly over the past few days (Figure 6), as warmer temperatures have promoted snowmelt and river discharge. We now see open water and flooding in the Horton, Hornaday, and Brock deltas. The ice is still present in Paulatuk Harbour and along the southern shore of the bay, but the first open water can be expected there soon. 5

6 Figure 6. Detail of Figure 5, showing the area around Paulatuk, including Franklin Bay and Darnley Bay in more detail. 6