The first snowfall of this season is already showing in some parts of Pennsylvania. This was the case in some locations in Westmoreland and Fayette counties, where, in fact, an alert is in effect that extends through Saturday morning. Indiana County has the same type of prevention warning.

This season already shows signs that it will be very particular and could be stronger.

For example, a "bomb cyclone" was lashing the western United States on Wednesday, bringing hurricane-force winds that have killed at least two people and left half a million without power.

Gusts of nearly 90 miles (145 kilometers) per hour were racing through the Pacific Northwest, toppling trees and power lines.

The National Weather Service said torrential rains dumped up to three inches (eight centimeters) of rain on parts of Oregon, Washington, and northern California.

Firefighters in the city of Lynnwood, near Seattle, said a falling tree had killed one woman at a homeless encampment, while another person died when a tree crashed into their house in nearby Bellevue.

"Trees are coming down all over the city & falling onto homes," Bellevue Fire Department wrote on social media. "If you can, go to the lowest floor and avoid windows. Do not go outside if you can avoid it."

About 500,000 homes were without power in Washington state as of Wednesday morning, according to the Poweroutage.us website.

The storm originally hit Washington but was now moving into Oregon and California. Forecasters say over a foot of rain could cause flooding at lower elevations and develop into blizzards over the mountains.

"The latest forecast calls for 12-16 inches of rainfall over northern California and far southwest Oregon into Friday," the Weather Prediction Center said in a bulletin.

"In the Cascades and mountains of northern California, a heavy snow threat will unfold as several feet of accumulation are possible.

"Strong winds will combine with snow to produce potential blizzard conditions."

Meteorologists say the cyclone's center is likely to remain well off the West Coast, limiting its destructive potential.

But the speed with which it formed and gathered power has led it to be classified as a "bomb cyclone."

Scientists say human-caused climate change is amplifying the destructive force of storms around the world.

Warmer oceans give up more water which provides additional energy to storms, increasing the strength of the wind.

The warming atmosphere also means storms can carry more water, resulting in heavier downpours.

Storm in Paris

The storm is also occurring in Europe. This Thursday, the phenomenon caused significant delays at Charles de Gaulle airport in Paris, where authorities asked airlines to cancel 10% of their flights, according to several sources.

The French Directorate General of Civil Aviation (DGAC) asked in a message to airlines to cancel 10% of their flights to or from Charles de Gaulle until midnight "because of the snow".

Teams from the ADP (Paris Airports) group "are mobilized to remove snow from the runways and de-ice the planes, and ensure flight safety," a company spokeswoman told AFP.

Snow began to fall heavily during the afternoon in Paris and its suburbs, after covering the northwest of France in white, complicating road traffic and causing flight delays.

More than 71 flights were affected at Charles de Gaulle airport, northeast of Paris, with more than an hour's delay on average during the afternoon. Orly airport, south of the capital, did not experience any delays.

The Caetano squall, marked by snow and strong winds, also caused some 235,000 homes to be without electricity on Thursday in western France, the Enedis company said.

With information from Agence France-Presse