Winter weather: Power outages, travel nightmare -- and snow in Vegas?

(CNN) -- It's turned travel into a nightmare, left regions freezing in bone-chilling darkness, and made snow over the neon lights of Las Vegas a possibility.

And the massive storm system that has affected millions of Americans is not over.

More sleet and subfreezing temperatures are predicted to hit areas from Dallas to Memphis until Sunday, and Little Rock, Arkansas, until Monday.

The nation's capital will not be spared from the cold either. Snow or sleet is forecast for Washington on Sunday.

In the central Appalachians through central New England, snow is expected into early Saturday morning, the National Weather Service said.

In addition to the plummeting temperatures, the drastic swings were startling. Hot Springs, Arkansas, experienced a record high of 75 on Wednesday. By Friday, it was in the middle of an ice storm.

Dark cloud over Dallas events

The Dallas/Fort Worth area is among the hardest hit. It will have a high of 27 degrees Saturday, a day after the Dallas/Fort Worth International Airport canceled almost 700 flights, about 80% of those scheduled.

The National Weather Service predicts a wintry mix of precipitation in the area through Sunday.

That downtown Dallas holiday parade scheduled for Saturday has been canceled for the first time in 26 years. The city also called off its annual marathon slated for Sunday, and the accompanying Health & Fitness Expo scheduled for Friday and Saturday.

More than 200,000 customers were without power in the Dallas-Fort Worth metro area Friday, according to energy provider Oncor.

This is the largest concentration of outages, with others scattered elsewhere in the state.

Storm deaths

In some cases, the weather has been deadly.

In Texas, a passenger was killed Thursday when a vehicle lost control and crashed into another car in Hockley County, the Texas Department of Public Safety said.

An Arkansas man was killed late Thursday when a tree fell on his camper in Pope County, the Department of Emergency Management said,

Highway Patrol officials in Oklahoma blamed at least one death, in Muskogee, on the weather.

In New Mexico, drivers dealt with icy roads. One person died in a semi crash near Clines Corners.

About 116 storm-related injuries have been reported in Oklahoma, including 48 falls, the state health department said.

States of emergency

Memphis called off the annual St. Jude Memphis Marathon, which was scheduled for Saturday. The city's lowest temperature will be around 18 degrees Saturday.

The governors of Tennessee and Arkansas declared states of emergency ahead of the worst of the storm.

Nearly 30,000 were without power in Arkansas, energy companies reported.

More coming

A wintry mix was forecast for Washington beginning about noon Sunday. The National Weather Service said it has the potential to be an ice storm from late Sunday afternoon through the evening hours, but temperatures are expected to rise above freezing by rush hour Monday.

A new storm entered the West, bringing snow to the Pacific Coast on Friday. It brought significant snowfall to Portland, Oregon, and there is a chance for rare snow in Las Vegas on Saturday.

Total snow accumulations will be up to 2 inches.

"The greatest chances for accumulation will be in Summerlin, especially in neighborhoods west of the 215 beltway," the National Weather Service said.

Las Vegas lows will hover around the mid-20s over the weekend.