In August 2010 a 265 km2 ice island calved from the Petermann Glacier innorthern Greenland. Soon after the initial calving event the mass broke intoseveral pieces, some of which exited Baffin Bay and drifted south toward theLabrador coast. By June 2011 PII-A, a large fragment of the initial PetermannIce Island, was situated offshore Labrador and in one week it had moved 225 kmdown the coast. Concern arose that if PII-A continued its trajectory it couldreach the Grand Banks by August 2011, posing a potential risk for existinginfrastructure in the offshore region of Newfoundland. To properly assess thepotential risk a realistic estimate of ice mass was necessary. This in turnrequired field measurements of the ice islands thickness. A three-day field program was carried out on the Petermann Ice Islands, PII-A and PII-A-a, from June 17–19, 2011. At this time PII-A and PII-A-a weresituated offshore Labrador, Canada, approximately 100 km northeast of the townof Rigolet. Geophysical survey methods, including Ground Penetrating Radar(GPR) and Seismic Reflection, were used to identify the base of the islands andobtain ice thickness measurements at various locations. Eight satellitetracking beacons were deployed on PII-A and one was deployed on PII-A-a. Ablation data, photographs and video footage were also obtained during theprogram. On July 22, 2011, PII-A was revisited while it was situated off thesouthern Labrador coast. GPR measurements were acquired at the pre-existingstations; the measurements allowed for deterioration rates due to surface andbasal melting to be calculated for PII-A. Results of the field measurementsindicate that ice thickness varied between 50 to 80 m on PII-A; the thicknessof PII-A-a was 30 m at a single survey location. Surface melt rates of 2.7–6.3cm day-1 were observed over a 1-day period in June. For the 35-day periodbetween June and July visits, average surface and basal melt of 5.0 cm day-1and 3.4 cm day-1, respectively, were calculated.

High resolution iceberg profiles are an essential element of an intelligent ice management toolkit. This paper describes field work undertaken during the spring and summer of 2015 to test our high resolution, rapid iceberg profiling system and presents some key results obtained. The profiling system uses a multibeam SONAR for the iceberg keel and a LIDAR for the iceberg sail. The system was used to collect 10 different iceberg profiles in the waters off eastern Newfoundland, ranging in size from 20m to 190m (waterline length). Profiling was performed at a speed of up to 6kts, allowing a 100m (waterline) iceberg to be profiled in under five minutes. The system is able to collect data even when significant vessel roll/pitch is evident and is able to compensate for iceberg movement during the profiling operation. Iceberg profiles created by C-CORE's system are validated by comparison with photographs and also via hydrostatic analysis.

No abstract

No abstract

The ISO 19906 standard provides guidance for the calculation of characteristic ice loads on offshore structures in arctic and cold regions. Ice failure is a complex process and the development and improvement of ice load models can be challenging, in large part because of difficulties obtaining full-scale data and scaling issues when extrapolating small-scale test data. Many of the ice load models referenced in ISO 19906 were developed during arctic exploration in the 70's and 80's. Typically, simplified geometries are assumed for both the structure and ice features in order to obtain analytic solutions; other simplifications may be incorporated appropriate for the specific applications considered and information available. A significant proportion of referenced models provide the maximum load during an interaction, rather than the development of the load over time. This can be a limitation were penetration into a thick ridge is limited by available driving force and kinetic energy. Given the large variety of ice conditions to which a structure may be subjected and the apparent randomness in ice fracture and damage mechanisms, there can be considerable variation in loads. Ice strength may be set to a characteristic fixed value, the ISO model for global sea ice loads is based on a relationship that considers ice thickness and contact width and is based on upper envelop fits to failure data. When determining the appropriate characteristic load on a structure, consideration should be given to exposure (i.e., the number and durations of ice interactions). Loads based on characteristic values for parameters such as ice thickness and ice strength could be inaccurate for scenarios where the exposure is significantly different than that on which the characteristic values were based. The application of probabilistic methods can be used to account for differences in exposure. While ISO 19906 references such methods, guidelines on implementation is limited. This paper examines issues in implementing available formulae for ice loads on fixed structures within a probabilistic framework and shows how characteristic ice loads differ depending on the model and assumptions used. The Sea Ice Loads Software (SILS), a probabilistic framework developed by C-CORE for calculating characteristic ice loads using the methods referenced in ISO19906, is used for the analyses and comparisons.