When tragedy strikes a major city or small town, it starts the clock on a crucial window of time — the giving period.

As images of human heartache emerge from manmade or natural disasters, many people long to help however possible and, as a result, open their pocketbooks. But experts say this benevolent spirit only lasts so long — generally no more than 60 days — because the media narrative moves on to the next big event, leaving the last disaster out of sight and out of mind.

“After that, there’s very few dollars that will be given to a disaster,” said Bob Ottenhoff, president and CEO of the Center for Disaster Philanthropy.

By that count, the donations rolling in to help victims of the Las Vegas shooting, which occurred Oct. 1, could dwindle significantly by the end of this month. And the money collected so far appears to trail other mass-casualty incidents, concerning the officials tasked with overseeing and distributing the funds.

The main fund to provide aid to the shooting victims, established by Clark County County Commissioner Steve Sisolak and Metro Police Sheriff Joe Lombardo, has raised about $11.5 million to date. A number of smaller funds may also pool their resources with the larger Las Vegas Victims’ Fund to more uniformly compensate the victims, but with the distribution of those funds more than three months away, companies and nonprofits have not made a final decision.

For instance, a spokeswoman for Zappos, which has independently crowdfunded more than $1 million with the Direct Impact Fund, said the company hasn’t decided where the funds will be allocated and whether they will join the larger Las Vegas Victims’ Fund. MGM Resorts — which donated $3 million in the wake of the shooting, more than a quarter of the Las Vegas Victims’ Fund’s current balance — will distribute at least half that amount directly to victims and use the rest to help first responders.

The bottom line: It’s unclear how much money will fill the pot for distribution to victims, but no matter how you slice it, the total amount lags what was collected after other high-profile tragedies.

More than $60 million in donations poured in after the Boston Marathon attack, which left three people dead and 264 others injured in April 2013. Three years later, when a gunman opened fire in an Orlando nightclub, people around the world responded by donating about $30 million. (The Boston metropolitan area includes twice as many residents as Las Vegas, which has a population that’s only slightly smaller than the greater Orlando area.)

The string of mass shootings dotting communities across the nation has resulted in what Ottenhoff chalks up to donor fatigue.

“It’s just one in a series of mass casualties that seem to go on endlessly,” he said, explaining the mindset behind why donations may be decreasing. “Nobody does anything about it. So who am I making that contribution to and for what purpose?”

The draft protocol for distributing money to victims, released by the Las Vegas Victims’ Fund last week, nods to its financial shortcomings. And yet the terror that unfolded on the Las Vegas Strip turned into the deadliest mass-shooting in modern American history, with 58 people killed, 546 injured and thousands more witness to the carnage.

“These funds are to be distributed to those who have been the most severely impacted by loss of life or physical injury,” the Las Vegas draft protocol states. “It is not possible to include all of the individuals impacted by 1 October and the criteria set by the (victims’ fund) in this protocol is by no means intended to devalue or minimize the trauma that has been experienced by a great many.”

In Las Vegas, claims will only be accepted from the families of the 58 deceased victims; victims who sustained permanent brain damage or paralysis and need continuous home medical assistance; and victims who required at least one night of hospitalization. It is unclear how many of the 546 injured fall into the latter two groups.

It’s a stricter criteria compared with other mass-casualty payouts. But not all recent incidents have inspired the same levels of generosity.

After the Boston Marathon bombing, the nonprofit fund established to help victims awarded $2.2 million each to the families of the three deceased individuals as well as three other people who were catastrophically injured — either by a double amputation or permanent brain damage. The fund also doled out $1.2 million each to 14 people who suffered a single amputation, $125,000 to $948,000 to 69 people hospitalized with injuries and $8,000 to 143 people who were injured but didn’t require overnight hospitalization.

In Orlando, $350,000 was awarded to the 49 families of the dead, between $65,000 and $300,000 to the 37 survivors depending on the number of nights they spent in the hospital, $35,000 to those who sought treatment in an outpatient setting and $25,000 each to the 182 clubgoers who were present at the time of the attack but escaped unharmed.

Meanwhile, only $2.4 million was raised for the victims of the San Bernardino mass shooting, which claimed the lives of 14 and left 24 more injured. The families of the deceased received $140,629 each, the injured received $5,000 plus $1,000 for each overnight hospital stay and the 37 people present during the attack received $2,993.

While the Boston and Orlando funds boasted more money, they also didn’t have nearly as many victims as Las Vegas to potentially compensate. Roughly 22,000 people attended the Route 91 Harvest country music festival the night of the Las Vegas attack.

“Las Vegas is the latest example that’s not very much money when you consider the number of the dead, the number of physically injured, catastrophic injuries and the hospitalized,” said Kenneth Feinberg, a Washington D.C. lawyer who specializes in awarding victim compensation and is aiding the Las Vegas Victims’ Fund. “$11, 15, 20, 30, 60 million wouldn’t get you very far.”

Scott Nielson, who chairs the volunteer-led Las Vegas Victims’ Fund Committee, said it’s important to remember these donations are a gift. The money isn’t designed to supplant health insurance, for instance. It’s a point echoed by Feinberg — essentially the country’s expert when it comes to divvying up tragedy-induced donations  — who grounds the situation in reality.

“Bad things happen to good people every day in this country and there’s no fund,” he said.

Plus, 2017 saw an unusually large share of disasters as hurricanes battered the coasts, wildfires swept through northern California and lone gunmen carried out attacks. A month after the Las Vegas tragedy, a shooter opened fire in a Texas church, where he killed 26 people, including children.

Ottenhoff expects philanthropic giving to set records this year as a result. Last year, American individuals, estates, foundations and corporations donated an estimated $390 billion to United States charities, according to Giving USA, which publishes an annual report.

Attention paid to other disasters may have spawned fewer donations to the Las Vegas fund, which surged initially and raised roughly $5 million in the first few days.

“First of all, one of the biggest factors in philanthropic contributions after disasters is media coverage,” Ottenhoff said. “It’s not just media coverage for a few days, but it’s extended media coverage. It’s a sad fact of life, but the more attention a disaster gets, the more contributions are going to be made.”

But Nielson remains hopeful that the holiday season and a benefit concert planned for Dec. 1 may unleash a new flood of donations for the Las Vegas victims.

“We’re grateful for everything that everyone has contributed,” he said. “This was a terrible, terrible event that orders a magnitude bigger than anything else like this. If people can find it in their hearts to give more, there’s just a lot of people who were really negatively impacted by this. There’s still a huge need in our community.”

Two 90-minute town halls to review the draft protocols will be held Tuesday at 10:30 a.m. and 6 p.m. at the Clark County Government Center Commission Chambers. Community members have until Dec. 8 to submit comments. After the final protocol is adopted on Dec. 15, it will be disseminated to all known eligible victims identified by hospitals, police, the FBI and local authorities, as well as those that signed up through the National Compassion Fund’s website.

All claim forms will be due by January 31, and payment distributions will begin March 5 on a rolling basis.

Disclosure: Steve Sisolak has donated $1,000 to The Nevada Independent. You can see a full list of donors here.