Despite the generally unfavorable conditions in the Mediterranean Sea, Rolf transitioned into a subtropical depression on 7 November, before becoming a tropical storm later that day.

[1][2] Rolf caused widespread flooding across southwestern Europe, especially in France and Italy, with the majority of the damage from the storm occurring in those two countries.

The storm forced numerous schools and businesses to close temporarily, and also caused significant damage to 300 farms in France.

Rolf killed 12 people, and was at the time, the costliest Mediterranean tropical-like cyclone on record, causing at least $1.25 billion (2011 USD, €926 million) in damages.

[7] On 6 November, the system moved into the western Mediterranean Sea in the direction of northwestern Italy, while gradually strengthening, before turning southward.

[2] Later on 7 November, Rolf turned westward, and slowly transitioned from an extratropical system into a subtropical depression over the abnormally-warm waters of the Mediterranean Sea,[7][12] which were at 17 °C (63 °F).

[13] With this transition, Rolf acquired a warm quasi-symmetric core, and organised convective rainbands wrapped around the center of the storm.

At 03:00 UTC on the same day, Rolf reached its peak intensity, attaining a minimum central pressure of 991 mb (29.3 inHg) and maximum 1-minute sustained winds of 85 km/h (53 mph).

[14][10][15][2] Rolf began to weaken on 9 November as it approached the French coastline, due to hostile conditions, with the storm's convection decreasing and its upper- and mid-level circulation centers becoming misaligned.

[14][18][7] As a tropical system, the warm core of Rolf persisted for a longer period of time compared to most of the other documented Mediterranean tropical-like cyclones.

[16][19] In both France and Italy, the heavy rainfall from the storm caused many rivers to overflow their banks, resulting in multiple cities being flooded and enormous property losses ensuing.

[22] The Genoa-Sestri Levante section of Highway A12 in Italy was closed, due to the flooding, and air and rail traffic in the region were suspended.

[27] On the evening of 6 November, Rolf spawned a tornado over Alassio, in the Province of Savona, damaging buildings and walkways in Piazza d'Italia, and flooding basements in the village of Barusso.

[30] Rolf also caused a landslide in the Province of Genoa that broke the natural gas line between Casella and Montoggio, which was estimated would require four to six months to repair.

[3] The Italian Government was criticized for the poor hydrogeological conditions in the city of Genova after Rolf, as well as the lack of safety measures for preventing the disaster; the aftermath led to the eruption of a political scandal.

[19] All of the rivers in the north, west, and central regions of the Alpes-Maritimes overflowed their banks, including: the Frayère in Auribeau, the Mourachone in Pégomas, the Siagne in Mandelieu, the Brague, the Béal, the Riou, the Cagne, the Loup, the Roya, the Vaïre, and the Var.

From 5–8 November, Rolf forced the evacuation of 2,500 people in the Argens region,[21] triggered blackouts that left 8,000 families without power, and required 1,100 rescues by French SP firefighters.

During that same period of time, Rolf caused widespread traffic disruptions, triggered multiple landslides, and also flooded numerous homes and apartments.

[37] In Catalonia, Rolf dropped a maximum total of 293.8 millimetres (11.57 in) of rainfall from 1 to 8 November, causing moderate flooding in the area, and cutting the power to 12,054 people in 33 municipalities.