Each year around July 4, the skies above East Palo Alto resident Maureen Larsson's neighborhood fill with the colorful bursts of large fireworks and the deafening booms of exploding mortars. The nightly sounds, which can go on for weeks before the national holiday, can be heard all over town.

"We've been here a long time and every year it's the same sadly destructive predictable thing: My husband and I are disrupted and stressed by months of explosions. We see at least one fire a year and hear about others caused by fireworks and know people whose property has been destroyed," Larsson said.

"This year the fireworks problem has worsened. It's still June and the social media posts about lost dogs and lost sleep are nonstop. Neighbors who're grappling with COVID, financial challenges and work demands are even more frazzled and there's no relief," she added. "People doing fireworks ... don't care how they impact their neighbors."

Menlo Park residents and Palo Altans who live near East Palo Alto say they are similarly frustrated.

Beth Guislin counted 120 explosions an hour on a recent night, her husband, John, said. It upsets her sleep and their dog is terrified.

There are also three or four group homes for veterans near the Guislins.

"I can't imagine it's good for them. I feel we need to address it," he said.

The fireworks have already ignited fires, such as a 2-acre blaze in an East Palo Alto field on June 4 that threatened homes and apartments, according to Menlo Park firefighters.

Local police departments say they are responding in force. There are ongoing criminal investigations, East Palo Alto police Chief Albert Pardini said by email.

"The entire patrol division is working to locate and arrest individuals in possession of illegal fireworks in East Palo Alto. I have several investigations in progress, but I can't reveal the details as it would tip off the suspects," he said.

"There seems to be a pattern of behavior that people walk out of their home, discharge a device and then go back into their home. A few minutes later, a different neighbor does the same thing, almost as if they are trying to have a competition to see who can make the loudest noise or launch the biggest airborne device," Pardini said, noting that the activity is occurring throughout the city.

"Our biggest help has been neighbors calling dispatch or using the tip line to give us a precise location so we can get to the site more quickly," he said.

It's not just the Midpeninsula that's being plagued with people setting off pyrotechnics — it's happening across the country.

New York has had a 426% increase in complaints about fireworks, he said, referencing news reports. The same problems are occurring in Los Angeles and other cities on the West Coast.

And why is it happening?

"It is believed that because of COVID-19: All firework shows are cancelled so people are making their own shows," he said.

Palo Alto police think there's a supply issue at play this year.

"One hypothesis that we've heard, which seems reasonable to us, is that due to cancellations of Fourth of July fireworks shows, there may be an overabundance of professional-grade fireworks available on illegal markets" Janine De la Vega, public affairs manager for the Palo Alto Police Department, stated in an email.

"Note this is purely speculative, but it could explain the significantly louder 'booms' that our residents are reporting now, compared to years past," she said.

Pardini said information suggests people are traveling to other states where it is legal to purchase fireworks. They are then illegally transporting the fireworks back.

Nevada law allows bottle rockets, sky rockets, roman candles, firecrackers, sparklers, missiles, aerial spinners, display shells and other aerial items, according to the American Pyrotechnics Association.

California prohibits these and other items: Only so-called "safe and sane" fireworks such as small items used on the ground — such as fountains, spinners and snap caps — are allowed in some counties. The "dangerous" fireworks, including bottle rockets and sparklers larger than 10 inches long or one-quarter inch in diameter, are banned.

Under California fireworks laws the possession or transport of illegal explosive devices is a misdemeanor subject to up to six months in county jail and a $1,000 fine. Possession of a large quantity of fireworks or explosive devices can result in up to three years in state prison and a fine up to $50,000.

Pardini said it's hard to catch violators because of the widespread activity.

"We attempt to track the discharges as they are occurring, but ... as my patrol officers hear or see the devices in the air, it is a challenge to determine which street they originated from," he said.

Palo Alto police haven't been able to verify any reports of fireworks or gunshots going off in Palo Alto.

"From ShotSpotter reports in East Palo Alto and from the observations of our own on-duty officers witnessing the fireworks occurring over East Palo Alto, we are confident that the source of the nightly issues is not in Palo Alto," De la Vega said. "We received one anonymous report over this past weekend that people were shooting fireworks off on the levees near our golf course. Our patrol division has been made aware of that tip and has stepped up patrols in that area as a result," she said.

FIreworks are also being set off in Menlo Park, and police there have seen an increase in complaints about them.

"The hotspots are in varied locations. While we have had a few calls west of El Camino, the bulk of the calls are throughout central Menlo Park and areas east of Middlefield Road and east of Highway 101," spokeswoman Nicole Acker said in an email.

Menlo Park police have not made any arrests nor fined the lawbreakers.

"Officers warn if they make contact with individuals," she said.

Police in all three cities have launched information campaigns. Pardini said East Palo Alto has placed banners at the University Avenue/Donohoe Street and University Avenue/Bay Road intersections to remind people that possession and discharge of fireworks are prohibited. The department has disseminated information in Pardini's weekly newsletter and distributed flyers in English and Spanish.

Palo Alto sent out a message to the community on June 16, which included information about how to report violators and city animal control officers' tips on how to help pets with anxiety.

The city also launched a fireworks education campaign in multiple city departments, providing information on safety and how to report fireworks or gunfire violations. It's best to call the 24-hour dispatch center at 650-329-2413 with an actual location, De la Vega said.

Acker said Menlo Park police have posted on social media and the city's blog, sent notifications and put up electronic sign boards regarding the city's no fireworks laws.

Menlo Park has not specifically coordinated any enforcement efforts with neighboring cities, Acker said. But Pardini said he has been communicating with other police chiefs and the San Mateo County sheriff.

Palo Alto officers have stepped up neighborhood patrols and in some open space areas during evenings as a deterrent, De la Vega said.

So far, the three cities' police chiefs have not pushed for new ordinances to address the illegal fireworks, however.

"A decision about stronger ordinances would be a decision of the council, but the current law makes it very clear it is illegal so it would be up to the council to evaluate whether the section needs to be changed," Pardini said.

Added De la Vega: "As we have had no verified reports of fireworks or gunshots being shot off in Palo Alto, stronger ordinances and fines in our city would have no impact on those in other jurisdictions.

"There are also a number of challenges to enforcement of fireworks laws. In order to make an arrest or to issue a citation, an officer needs to be able to witness the violation or otherwise catch those responsible in possession of fireworks, or alternately, have a witness who can identify the suspect who is willing to sign a private person's arrest.

"When we have very few witnesses overnight (other than aural 'witnesses'), and considering our officers have to be in the right place at exactly the right time to witness a violation themselves, enforcement is difficult."

Larsson said there are no easy answers.

"It's a very difficult problem to solve, preferably requiring a culture shift that doesn't include further gentrification," she said. "We'd like to see an annual meeting with city leaders, first responders, Community Emergency Response Team members, big landlords, neighborhood representatives and other stakeholders to ultimately reduce the usage of fireworks."