Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions, we analyze 1.5‐ to 10‐Hz seismic tremor that we associate with subglacial water flow, hat is, glaciohydraulic tremor, at Taku Glacier, Alaska, throughout the 2016 melt season. We use frequency‐dependent polarization analysis to estimate glaciohydraulic tremor propagation direction (related to the subglacial conduit location) and a degree day melt model to monitor variations in melt‐water input. We suggest that conduit formation requires sustained water input and that multiconduit flow paths can be distinguished from single‐conduit flow paths. Theoretical analysis supports our seismic interpretations that subglacial discharge likely flows through a single‐conduit in regions of steep hydraulic potential gradients but may be distributed among multiple conduits in regions with shallower potential gradients. Seismic tremor in regions with multiple conduits evolves through abrupt jumps between stable configurations that last 3–7 days, while tremor produced by single‐conduit flow remains more stationary. We also find that polarized glaciohydraulic tremor wave types are potentially linked to the distance from source to station and that multiple peak frequencies propagate from a similar direction. Tremor appears undetectable at distances beyond 2–6 km from the source. This new understanding of the spatial organization and temporal development of subglacial conduits informs our understanding of dynamism within the subglacial hydrologic system.

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Many studies have defined the interrelationships between climate, forest disturbance, and runoff at small scales (<100 km2), but few have translated these relationships to large watersheds (>500 km2). In this study, we explore the relationship between climate, extreme forest fire seasons, mountain pine beetle (MPB) outbreaks, and runoff in eight large watersheds within the Fraser and Peace drainage basins in British Columbia (BC), Canada from 1981–2019. Using a climate index based on precipitation and air temperature anomalies, we find extreme forest fire seasons (those that burned >5% of a watershed's area) are most likely to occur when a warm/dry summer is preceded by multiple seasons of cool/wet conditions. Using the climate suitability class (CSC) model to explore the relationship between climate and MPB outbreaks, we validate previous findings that lower‐than‐average precipitation, warm growing season temperatures, and lack of extremely cold temperatures during winter are connected to MPB outbreaks within central BC. However, the CSC model needs improvements to accurately assess MPB suitability in northern watersheds that are located outside the model's calibration region, either through weighted variables or lower degree day thresholds. Minimal runoff response occurs from these forest disturbances, with the most prominent runoff change being related to the 2014 fire season in the Osilinka and Mesilinka watersheds. The limited effects of forest disturbance on annual runoff are likely related to large watershed sizes, low percentages of disturbed area in some study watersheds and post‐MPB forest dynamics. These results provide valuable insight into the interrelationships of climate, forest disturbance and runoff in large Canadian boreal forested watersheds.

Glacial hydraulic tremor (GHT) can be monitored to observe changes in location and distribution of water flow beneath glacial ice, allowing the spatiotemporal evolution of subglacial hydrology to be studied continuously and remotely. We use frequency-dependent polarization analysis (FDPA) to classify types of GHT and assess its spatio-temporal extent beneath Rhonegletscher, Switzerland, in a continuous seismic record through 2018 and 2019 at three ice-proximal bedrock-based seismometers. We determine the frequency bands composing the GHT and calculate back azimuth angles pointing to a previously known subglacial channel. We also inspect the relationship between GHT seismic power and water discharge from the glacier to compare daily and seasonal shifts with the observed GHT. We observed the seasonal shift from a distributed system to a channelized system, and our dataset allowed comparison of channel locations within and across seasons, with implications for sediment evacuation and bed erosion. The successful use of this method to assess GHT previously on Taku glacier (the methods of which this project follows) and now Rhonegletscher shows that existing ice-proximal passive seismic installations can be used to easily and continuously monitor subglacial hydraulic activity.