ENGLEWOOD CLIFFS, N.J. -- A pair of brush fires broke out in the Palisades area of New Jersey early Friday morning, sending clouds of smoke across the Hudson River and into New York City.

Dozens of firefighters converged on the area near Exit 1 on the Palisades Parkway, about one mile north of the George Washington Bridge. One northbound lane of the parkway is closed, and Henry Hudson Drive is also shut down.

Around 2:45 p.m., the New Jersey Department of Environmental Protection's Forest Fire Service posted on social media saying the Englewood Cliffs fire is about 30% contained and spans approximately 39 acres. A smoke advisory is in place. The cause of the fire is unknown at this time.

The steep, wooded area is situated between the Palisades Parkway and the Hudson River. It's full of dry, dense brush and is relatively inaccessible, but the river acts as a natural barrier and there are not many buildings nearby.

The Forest Fire Service said the fire is not threatening any structures and there are no evacuations.

A helicopter capable of carrying up to 350 gallons has been dropping water from above, while crews and fire engines attack the blaze on the ground.

Some onlookers stopped by the Rockefeller Lookout area to capture photos and videos of the scene.

"There's no houses around here, it's preserved. So it's just going to destroy the nature, it's not going to destroy anybody's home... unless it jumps over the highway, which I doubt," hiker Nancy McLaughlin said. "They should be able to handle this. These firemen? They're going to knock it out."

"I just saw the fogginess and was like, what's going on? We came here, then we saw," said hiker Yuda Katz.

The area is popular with walkers and hikers, but the trails were closed to the public Friday.

Smoke creates nuisance in New York City

Across the river in New York City, residents in Upper Manhattan and parts of the Bronx also woke up to a smell of smoke.

"It was just a blaze of fire. And then my husband woke up at 3:30 and just had to shut the windows, because the smoke was so bad," one Spuyten Duyvil resident said. "This has gotten worse since I got up this morning."

Some residents said they could see the brush fire from their apartment windows overnight.

"We realized the smoke was coming in, and then he said he could see the flames. By the time I got out there, probably around 6:45, you could just see a lot of smoke," another resident added.

As the sun came up, video from Chopper 2 showed a white plume billowing across the Hudson.

The FDNY responded to several calls about smoke in Upper Manhattan and the Bronx, though it appeared many or all were linked to the New Jersey fires.

"Wildfires outside of NYC means you may smell smoke. Air quality overall forecast for today is 48, and current conditions are at 58 (Moderate)," the city's Office of Emergency Management posted on social media Friday morning.

Experts say some people with sensitivities may experience mild health effects at that level.

"The complicated issue here is wildfire smoke itself contains a whole bunch of different compounds ... We don't always know what's burning," pulmonologist Chirag Shah said.

"It will certainly have an impact on people. We wouldn't expect a level of moderate AQI to cause a public health impact in and of itself. Typically, we would say that if you're particularly sensitive, you'd wanna look for symptoms ... watchful of any coughing or shortness of breath," said Kevin Edwards, senior technical director of air quality and sustainability for AKRF.

By Friday afternoon, the air quality in Upper Manhattan and the Bronx improved to "good."

Red Flag Warning extended in Tri-State Area

A Red Flag Warning has been extended through 6 p.m. Saturday across the Tri-State Area due to a combination of dry and windy conditions.

Firefighters in New Jersey have battled at least three wildfires in recent days, including one in Jackson Township that officials say is about 80% contained after burning through 350 acres.

"Crews are obviously getting tired because they've been running, running, running, but we will continue to do our job the best we can," said Jeremy Webber, with the New Jersey Forest Fire Service.

The fire risk is considered extreme across the Garden State, as the drought continues. October was the driest month on record, with less than an inch of rain.

The risk will remain moderate-to-high Saturday before decreasing Sunday into Monday when we could finally see some more rainfall.

Residents are being asked to stay vigilant. Officials say anything from a cigarette to dumped ashes to flying dry leaves to malfunctioning equipment can spark a fire.

"If they're mowing their lawn or they're doing leaves and stuff, just remember that fuels are very dry and they are very receptive to any sort of ignition source," Webber said.

So what should you do if you spot a wildfire? If you're driving, AAA says to keep calm and keep your windows closed.

"Couple concerns when dealing with wildfires, mainly the smoke is going to be decreasing visibility. So you really want to treat it as if it's a very foggy day," AAA Northeast senior spokesperson Mark Schieldrop told CBS News New York. "That means drive a little slower, increase your following distance, make sure your lights are on so you're visible, and give yourself that additional time to react and slow down if there's something in front of you."

He also said to make sure your vehicle's re-circulation button is turned on, so the air filter can help reduce particulate matter.

When it comes to cleaning ash off your car, don't let it sit for too long.

"It's not like dirt, it's very gritty and it's abrasive. So you want to start to wipe that ash away, very gently, with a soft cloth or a microfiber cloth or a duster," Schieldrop said. "You want to make sure you wipe down the windshield wipers too, because if you turn them on and there's still ash residue on there, that's going to grind into your windshield."

contributed to this report.