The June 2013 Alberta Catastrophic Flooding Event: Part 1-Climatological aspects and hydrometeorological features

Liu, A. Q.; Mooney, C.; Szeto, K.; Thériault, J. M.; Kochtubajda, B.; Stewart, R. E.; Boodoo, S.; Goodson, R.; Li, Y. et Pomeroy, J. (2016). « The June 2013 Alberta Catastrophic Flooding Event: Part 1-Climatological aspects and hydrometeorological features ». Hydrological Processes.

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Résumé

In June 2013, excessive rainfall associated with an intense weather system triggered severe flooding in southern Alberta, which became the costliest natural disaster in Canadian history. This article provides an overview of the climatological aspects and large-scale hydrometeorological features associated with the flooding event based upon information from a variety of sources, including satellite data, upper air soundings, surface observations and operational model analyses. The results show that multiple factors combined to create this unusually severe event. The event was characterized by a slow-moving upper level low pressure system west of Alberta, blocked by an upper level ridge, while an associated well-organized surface low pressure system kept southern Alberta, especially the eastern slopes of the Rocky Mountains, in continuous precipitation for up to two days. Results from air parcel trajectory analysis show that a significant amount of the moisture originated from the central Great Plains, transported into Alberta by a southeasterly low level jet. The event was first dominated by significant thunderstorm activity, and then evolved into continuous precipitation supported by the synoptic-scale low pressure system. Both the thunderstorm activity and upslope winds associated with the low pressure system produced large rainfall amounts. A comparison with previous similar events occurring in the same region suggests that the synoptic-scale features associated with the 2013 rainfall event were not particularly intense; however, its storm environment was the most convectively unstable. The system also exhibited a relatively high freezing level, which resulted in rain, rather than snow, mainly falling over the still snow-covered mountainous areas. Melting associated with this rain-on-snow scenario likely contributed to downstream flooding. Furthermore, above-normal snowfall in the preceding spring helped to maintain snow in the high-elevation areas, which facilitated the rain-on-snow event.

Type: Article de revue scientifique
Informations complémentaires: This is the peer reviewed version of the following article:Liu, A.Q., Mooney, C., Szeto, K., Thériault, J.M., Kochtubajda, B., Stewart, R.E., Boodoo, S., Goodson, R., Li, Y. et Pomeroy, J. (2016). The June 2013 Alberta Catastrophic Flooding Event: Part 1—Climatological aspects and hydrometeorological features. Hydrological Processes, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/hyp.10906/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Mots-clés ou Sujets: Alberta flooding, climate, hydrometeorological features, synoptic conditions, moisture transport, rain-on-snow
Unité d'appartenance: Faculté des sciences > Département des sciences de la Terre et de l'atmosphère
Déposé par: Julie Mireille Thériault
Date de dépôt: 17 nov. 2016 14:08
Dernière modification: 01 déc. 2017 00:10
Adresse URL : http://archipel.uqam.ca/id/eprint/9079

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