eccc climate specialists have also assessed trends in short-duration rainfall patterns affecting flash flooding. data include annual maximum observations at climate stations, documented in engineering climate datasets. eccc notes: "short-duration (5 minutes to 24 hours) rainfall extremes are important for a number of purposes, including engineering infrastructure design, because they represent the different meteorological scales of extreme rainfall events." a "general lack of a detectable trend signal", meaning no overall change in extreme, short-duration rainfall patterns, was observed. in relation to design criteria used for urban drainage design (e.g., intensity-duration-frequency (idf) statistics), the evaluation "shows that fewer than 5.6% and 3.4% of the stations have significant increasing and decreasing trends, respectively, in extreme annual maximum single location observation amounts." on a regional basis, southwest and the east (newfoundland) coastal regions generally showed significant increasing regional trends for 1 and 2 hour extreme rainfall durations. decreasing regional trends for 5 to 15 minute rainfall amounts were observed in the st. lawrence region of southern quebec and in the atlantic provinces.