Italy has seen its fair share of rainfall this past week, especially in the northern tier of the country including the city of Milan. Trouble started off in early November when a system originating from the Mediterranean Sea brought abnormal amounts of moisture into the region, producing heavy rainfall over a sizeable portion of Italy. This system, associated with a slow moving negatively tilted trough, dug down into southwestern Europe and triggered isolated thunderstorms and widespread rain. The system dumped copious amounts of rainfall – over 100mm fell in northern parts of Italy. With already saturated grounds from previous events in the past few weeks, this meant trouble for some villages.
Milan and surrounding areas saw the worst of the flooding. Subway systems were inundated with water, streets were flooded with over a foot of water and schools were forced to close. Two rivers in the region, the Seveso and Lambro, overflowed their banks and contributed to the flooding. The flooding is responsible for five deaths and estimated damages in excess of 100 million dollars.
Significant repairs will have to be done to this central Milan canal wall and road which collapsed due to the saturated ground below that gave way. (Source: @SimoneEneaRicco)
Northern Italy will remain soggy over the weekend, with another 10-20mm expected due to the same slow moving trough which continues to linger. Throughout November Milan usually sees about 100mm of precipitation, but just half-way through they have already surpassed it.
By the beginning of next week there’s a good chance that things will start to clear up as a weak ridge builds in.
This past year several historical events have taken place – from right here in Canada, to Tornado Alley, to half-way across the globe in the Philippines. The post this week will feature a countdown of this year’s top 3 severe weather events.
3. Alberta Floods – June 19th to June 22nd
This event was fuelled by moisture from the Gulf of Mexico that was able to stream all the way north to southern Alberta, where an upper low was positioned. The situation would not have been as bad if a blocking pattern wasn’t in place further north, stalling the upper level low over southern Alberta. As all this moisture was pushed up the Rockies, condensed, and further, fell as precipitation leading to significant flooding along the foothills. Extreme rainfall amounts were recorded in Canmore at 220mm (half their annual rainfall) and High River which recorded 325mm, both in less than two days.
Rainfall totals for Alberta up to the 21st of June. (Source: AB Environment)
This severe weather event was the costliest in Canadian history, reaching two billion dollars in damages. An estimated 100,000 residents were forced to evacuate, a total of 32 communities were in a state of emergency and 2,000 armed forces were brought in to help out. Unfortunately, four people lost their lives in this event.
A few more facts from the event:
The Saddledome (home of the Calgary Flames hockey team) flooded up to the 10th row of seats
Over 1,000km of roads were destroyed
Calgary received 88% of their average monthly precipitation within 48 hours
2. Moore Tornado – May 20th
On the afternoon of May 20th, one of the worst scenarios possible occurred; tornadic supercells spawned a strong tornado on the ground and tore through a city of 50,000 people. Conditions were ideal for supercells to develop as the CAPE was in the 5000J/kg, shear was in the 50kt range and a dryline trigger was present. The city of Moore, Oklahoma took a direct hit from an EF-5 tornado. The massive tornado, which had a maximum width of 2.1km, raced across Oklahoma for 27km before it eventually lifted after passing through Moore.
Radar scan (reflectivity and velocity) at the time the tornado hit Moore. Large debris ball present on the radar over the city as well as a tornado vortex signature. (Source: Personal files/GR3 radar)
Damage in Moore was severe as whole neighbourhoods were swept off the map. An estimated 1,150 homes were destroyed with a total of two billion dollars in damages. The tornado also took the lives of 24 people and injured 377, but the toll could have been significantly higher had the NWS not put out a strongly worded warning for the Oklahoma City/Moore area a good 15 minutes before the tornado arrived.
Interestingly enough, 11 days later the widest tornado on record touched down in El Reno, Oklahoma measuring 4.2km in width, just 60km west of Moore. This tornado was rated an EF-3 and sadly took the lives of 8 people, including the respected researcher and storm chaser Tim Samaras.
A few significant facts from the Moore tornado:
The Storm Prediction Center had issued a moderate risk with a 10% hatched tornado risk for the area that day
A 10-ton water tank was thrown one kilometer away
The tornado was on the ground for almost one hour
1. Super Typhoon Haiyan – November 3rd to November 11th
Our top weather story is one that is still fresh in our minds. Typhoon Haiyan (also known as Typhoon Yolanda) made landfall in the Philippines as a strong category five typhoon, bearing winds of approximately 315km/h and a central pressure below 900mb. With these values, Haiyan would be the strongest tropical cyclone to ever make landfall.
IR image of super typhoon Haiyan 5 hours before it made landfall in the Philippines. (Source: Co. State University)
In total, 7,000 people perished from this storm, with still a thousand missing, making it the deadliest typhoon on record in the Philippines. Extreme damage totaling an estimated 1.5 billion dollars occurred mainly due to wind and storm surge. Tacloban was the hardest hit city as the storm surge of 6m took out buildings over one kilometer inland. 90% of the city was reported to be destroyed.
A few significant facts from super typhoon Haiyan:
11 million people were affected by Haiyan
Haiyan made a second landfall in Vietnam as a category one typhoon
4 typhoons made landfall in the Philippines in 2013 (Utor, Nari, Krosa, Haiyan)
An extremely powerful cyclone churning in the Bay of Bengal is targeting India’s east coast and is expected to make landfall this morning. This is one of the strongest cyclones India has seen in recent history and the strongest since 1999. Phailin has maintained category five status since Friday afternoon and is expected to only slightly weaken to a high end category four (as its eyewall moves over land) before making landfall. Conditions were primed for quick intensification on Thursday; SSTs approaching the 30°C mark and shear quite low. Phailin went from a tropical cyclone to category four on Thursday thanks to these ideal conditions for intensification. Already, India has evacuated tens of thousands of residents from low lying coastal areas but Phailin still has the potential to wreak much havoc on India. Already one death has been reported associated with a tree falling onto a house as of Friday night.
Incredible image of Phailin just before it makes landfall; a well defined eyewall and very cold cloud tops are present showing that the storm is well-organized. (Source: CIMSS)
Storm surge will be a real problem with this cyclone – a forecasted 11 foot storm surge is expected to arrive as Phailin makes landfall near Brahmapur. The good news is that the coastline goes up in elevation fairly quickly as you move inland, therefore residents that should be most concerned with storm surge should be the ones that live near shorelines. With category five cyclones like this one winds as well as flooding problems are almost a given. In this case, winds will be sustained over 240km/h, gusting over 300km/h, and anywhere from 200mm to 350mm can be expected to fall around where Phailin makes landfall. The cyclone is expected to move inland and die off fairly quickly as it moves over land as opposed to being over warm ocean waters.
Sea surface temperatures, overlayed with shear. Note the low shear values (5-10 knots) and SSTs between 29°C and 30°C; sufficient to sustain category five storms. (Source: CIMSS)
Another storm; typhoon Nari is currently threatening Vietnam to make landfall at the beginning of next week. It is still recovering from its passage over the rugged islands of the Philippines but is expected to strengthen to a category three typhoon over the South China Sea before landfall. Models are suggesting yet another typhoon to spin up behind Nari but this one is expected to take a turn towards Japan. So, overall a very active weekend and upcoming week cyclone and typhoon-wise!
This spring has been disastrous flood-wise across the globe; hundreds of billions of dollars of damage to crops and infrastructure from a few significant floods such as the Chinese floods, European floods and closer to home; Albertan floods as talked about in last week’s EIWN. Extreme flooding continues this week, most notably in Australia’s New South Wales state.
In the past few days coastal areas of New South Wales have received copious amounts of rain. Consequently, flood evacuations have had to be issued for a few towns just outside of Sydney (Richmond Lowlands, Pitt Town, Gronos Point). The Warragamba Dam, located to the west of Sydney, was overwhelmed by the 150mm of rain that fell in a 24 hour period starting Wednesday, prompting for the flood evacuations. Many roads and a few key bridges in the area had to be shut down because of the overland flooding. In addition, a few search and rescue missions have had to be executed because of people trapped in floodwaters. Thankfully no casualties have been reported as of yet related to this flooding.
Rainfall map for the past 7 days as of Friday. Circled in red the area experiencing flooding, localized areas of 200mm+. (Source: Australia’s BoM)
It appears as though a lingering trough of low pressure is to blame for all the rain on the eastern coast of Australia on Wednesday. Sydney and surrounding areas get on average about 130mm of rain for the whole month of June. Compared to this past week where in some areas 200mm (or more) have already fallen, these areas have already doubled their average rainfall for June, significant flooding is not surprising. This weekend appears to bring more rain to the coast of New South Wales, though not another significant rainfall event.
