TY  - JOUR
PY  - 2021//
TI  - Characterisation of initial fire weather conditions for large spring wildfires in Alberta, Canada
JO  - International journal of wildland fire
A1  - Tymstra, Cordy
A1  - Jain, Piyush
A1  - Flannigan, Mike D.
A1  - Tymstra, Cordy
A1  - Jain, Piyush
A1  - Flannigan, Mike D.
SP  - 823
EP  - 835
VL  - 30
IS  - 11
N2  - We evaluated surface and 500-hPa synoptic weather patterns, and fire weather indices from the Canadian Forest Fire Danger Rating System for 80 large wildfires during 1990-2019 in Alberta that started in May and grew to over 1000 ha. Spread days were identified during the first 4 days of wildfire activity. We observed two distinct synoptic weather patterns on these days. Pre-frontal and frontal passage activity was the predominant feature associated with 48% of the calendar spread days. Strong south-south-east winds from a surface high centred east of Alberta (west of Hudson Bay) and supported by an upper ridge, and a surface low located south-west of the ridge occurred on 26% of the calendar spread days. Surface analysis indicates the spring wildfire season in Alberta is driven by very high to extreme Initial Spread Index, a rating of the expected wildfire rate of spread based on Fine Fuel Moisture Code and wind. Very high to extreme values of Buildup Index, a rating of the amount of fuel available for consumption, are not a prerequisite for large wildfires in May. For Alberta, this means large wildfires in May can occur after only a few days of dry, windy weather.<p />  <p>Language: en</p>
LA  - en
SN  - 1049-8001
UR  - http://dx.doi.org/10.1071/WF21045
ID  - ref1
ER  -