The properties of streamlined glacial landforms and palaeo-flow indicators in the valleys of Viðidalur, Vatnsdalur and Sv ınadalur in northern Iceland were quantified using spatial analyses. Drumlins and mega-scale glacial lineations (MSGL) were visually identified using satellite imagery from Google Earth, the National Land Survey of Iceland (NLSI) Map Viewer and Landsat satellites, and using aerial photographs from the NLSI. A semi-automated technique was developed using ENVI to determine regions in northern Iceland likely to contain streamlined landforms. The outlines of the identified landforms were manually delineated in Google Earth, and all analyses were conducted in ArcGIS using a 20 m digital elevation model (DEM) of Iceland from the NLSI. Smaller features such as flutes, grooves and striations were measured in the field. At least 543 drumlins and 90 MSGL were identified in the three valleys. Average elongation ratios for Viðidalur, Vatnsdalur and Sv ınadalur are 4.3:1, 5.2:1 and 6.7:1, respectively. The average density of streamlined landforms is 2.34 landforms per 1 km 2 . Striations and orientation data of the drumlins and MSGL demonstrate ice flow to the northwest into H unafl oi. Parallel conformity is higher in the valley of Sv ınadalur (9°standard deviation) than in Viðidalur (12°) and Vatnsdalur (16°). Packing values are generally higher in the centre of each valley. The properties of streamlined landforms in the valleys of Viðidalur, Vatnsdalur and Sv ınadalur support the presence of palaeo-ice stream activity on northern Iceland. Palaeo-ice streams flowed from these regions into H unafl oi, supplying ice to the margin of the Iceland Ice Sheet during the Last Glacial Maximum. These palaeo-ice streams provide a mechanism for ice centres from the mainland of Iceland to reach the shelf-slope break.

The formation of lakes as glaciers retreat can potentially influence stream temperature and enhance catchment water losses via evaporation. This study quantified the summer water and energy budgets and thermal regime of an ice‐contact proglacial lake below Bridge Glacier, British Columbia, to link ongoing glacier retreat with downstream effects. The ice‐proximal and distal portions of the lake behave differently due to a mid‐lake recessional moraine, against which icebergs are pinned by the dominant katabatic wind. Iceberg cover of the ice‐proximal basin ranged from 16% to 75%. Temperature profiles in the ice‐proximal basin were dominantly near‐isothermal at 1 to 1.4°C, with the exception of diurnal warming of the top 1 m of water and the presence of a colder layer near the lake bed at some sites, presumably caused by subglacial discharge of turbid water. Subaqueous iceberg melt limited warming by consuming heat from the water column. The distal basin exhibited varying degrees of thermal stratification, with turbidity inferred to have a greater influence on water density than temperature. Most of the warming between lake inflow and outflow occurred in the distal basin, where net radiation was the dominant surface energy input and net lateral advection the dominant energy sink. As a result of the suppressed water temperature, humidity gradients over the lake favoured condensation, not evaporation. Estimates of iceberg melt volume for 2013 exceeded glacier discharge into the lake. Therefore, when the glacier eventually becomes land‐terminating, icebergs are expected to disappear within a year, resulting in higher water temperatures both in the lake and downstream. Higher lake temperatures could also cause an eventual shift from condensation to evaporation, which would tend to reduce catchment water yield over and above reductions associated with loss of glacier area.

Iceberg discharge is estimated to account for up to 50% of the freshwater flux delivered to glacial fjords. The amount, timing, and location of iceberg melting impacts fjord‐water circulation and heat budget, with implications for glacier dynamics, nutrient cycling, and fjord productivity. We use Sentinel‐2 imagery to examine seasonal variations in freshwater flux from open‐water icebergs in Sermilik Fjord, Greenland during summer and fall of 2017–2018. Using iceberg velocities derived from visual‐tracking and changes in total iceberg volume with distance down‐fjord from Helheim Glacier, we estimate maximum average two‐month full‐fjord iceberg‐derived freshwater fluxes of ~1,060 ± 615, 1,270 ± 735, 1,200 ± 700, 3,410 ± 1,975, and 1,150 ± 670 m3/s for May–June, June–July, July–August, August–September, and September–November, respectively. Fluxes decrease with distance down‐fjord, and on average, 86–91% of iceberg volume is lost before reaching the fjord mouth. This method provides a simple, invaluable tool for monitoring seasonal and interannual iceberg freshwater fluxes across a range of Greenlandic fjords.

There has been increasing attention over the last decade to the potential effects of glacier retreat on downstream discharge and aquatic habitat. This study focused on streamflow variability downstream of Bridge Glacier in the southern Coast Mountains of BC between 1979 and 2014, prior to and during a period in which the glacier experienced enhanced calving and rapid retreat across a lake‐filled basin. Here we combined empirical trend detection and a conceptual‐parametric hydrological model to address the following hypotheses: (1) streamflow trends in late summer and early autumn should reflect the opposing influences of climatic warming (which would tend to increase unit‐area meltwater production) and the reduction in glacier area (which would tend to reduce the total volume of meltwater generated), and (2) winter streamflow should increase because of displacement of lake water as ice flows past the grounding line and calves into the lake basin. In relation to the first hypothesis, we found no significant trends in monthly discharge during summer. However, applying regression analysis to account for air temperature and precipitation variations, weak but statistically significant negative trends were detected for August and melt season discharge. The HBV‐EC model was applied using time‐varying glacier cover, as derived from Landsat imagery. Relative to simulations based on constant glacier extent, model results indicated that glacier recession caused a decline in mean monthly streamflow of 9% in August and 11% in September. These declines in late‐summer streamflow are consistent with the results from our empirical analysis. The second hypothesis is supported by the finding of positive trends for December, January, and February discharge. Despite the modelled declines in late‐summer mean monthly streamflow, recorded discharge data exhibited neither positive nor negative trends during the melt season, suggesting that Bridge Glacier may currently be at or close to the point of peak water. Further analysis of the impact of lake‐terminating glaciers on downstream discharge is needed to refine the peak water model. Copyright © 2016 John Wiley & Sons, Ltd.