1925 serum run to Nome participant Leonhard Seppala
Problem solving
At the January 24 meeting of the board of health, superintendent Mark Summers of the Hammon Consolidated Gold Fields proposed a dogsled relay using two fast teams. One would start at Nenana, Alaska, the closest railhead on the Alaska Railroad, and the other at Nome, and they would meet roughly halfway in the town of Nulato. The trip from Nulato to Nome normally took 30 days. Curtis Welch estimated that the serum would last only six days under the brutal conditions of the trail. Summers's employee, the Norwegian sled dog trainer and musher Leonhard Seppala, was chosen for the 630-mile (1,014 km) round trip from Nome to Nulato and back. He had previously made the run in a record-breaking four days, won the All-Alaska Sweepstakes three times, and had become famous for his athletic ability and rapport with his Siberian huskies. His lead dog, the 12-year-old Togo, was equally famous for his leadership, intelligence, and ability to sense danger.
Maynard proposed flying the antitoxin by plane. In 1925, planes were a relatively new technology, and Alaska's harsh winter weather made them unreliable. Several test flights had been conducted the previous year between Fairbanks and McGrath, Alaska, to determine how well a reliable aircraft could handle the winter conditions. The longest test flight flew a distance of only 260 miles (420 km), a little under half the necessary distance between Nenana and Nome. Furthermore, the only planes operating in Alaska in 1925 were three vintage biplanes, which had been dismantled for the winter; their open cockpits and water-cooled engines would make these planes unfit for the trip as well. Although it was potentially quicker, the proposal to deliver the antitoxin by flight was rejected by the board of health. Instead, they voted unanimously for the dogsled relay. Seppala was notified that evening and immediately began preparations for the trip.
The U.S. Public Health Service had located 1.1 million units of serum in West Coast hospitals which could be shipped to Seattle, Washington, and then transported to Alaska. The next ship north would not arrive in Seattle until January 31, and it would take another six to seven days to arrive in Seward. On January 26, however, 300,000 forgotten units of the antitoxin were located in a hospital in Anchorage. The supply was wrapped in glass vials, then padded quilts, and finally a metallic cylinder weighing a little over 20 pounds (9 kg). At Governor Scott Bone's order, it was immediately shipped to Nenana and arrived the next day. While not sufficient to defeat the epidemic, the 300,000 units could slow the spread of the disease until the larger shipment arrived.
The temperatures across the Alaskan Interior were at 20-year lows due to a high pressure system from the Arctic; in Fairbanks the temperature was −50 °F (−46 °C). Winds reaching speeds of 25 mph (40 km/h) caused snow to cover the Alaska Panhandle in snowdrifts up to 10-foot (3 m) tall. Travel by sea was hazardous, and across the Interior, most forms of transportation shut down. Furthermore there were limited hours of daylight to fly due to the polar night.Connection on Norton Sound
Leonhard Seppala and his dog sled team, with his lead dog Togo, travelled 91 miles (146 km) from Nome from January 27 to January 31 into the oncoming storm. They took the shortcut across the Norton Sound, and headed toward Shaktoolik. The temperature in Nome was a relatively warm −20 °F (−29 °C), but in Shaktoolik, the temperature was estimated at −30 °F (−34 °C), and the gale force winds causing a wind chill of −85 °F (−65 °C). 
Henry Ivanoff's team ran into a reindeer and got tangled up just outside Shaktoolik. Seppala still believed he had more than 100 mi (160 km) to the original relay point in Nulato to go and had raced to get off the Norton Sound before the storm hit. He was passing the team when Ivanoff shouted, "The serum! The serum! I have it here!": 207 Seppala turned around with the serum but it was dark by the time he got to Ungalik. But with the news of the worsening epidemic Ivanoff had shared, he decided not to stop and once again set out to brave the storm across the 20 miles (32 km) of exposed open ice of the Norton Sound. The temperature was estimated at −30 °F (−34 °C), but the wind chill with the gale force winds was −85 °F (−65 °C). Togo led the team in a straight line through the dark, and they arrived at the roadhouse in Isaac's Point on the other side at 8 pm. In one day, they had travelled 84 mi (135 km), averaging 8 mph (13 km/h). The team rested, and departed at 2 am into the full power of the storm.
During the night, the temperature dropped to −40 °F (−40 °C), and the wind increased to storm force (at least 65 mph [105 km/h]). While they slept, it had blown out to sea all the ice Seppala had just crossed. There was still some ice close to shore for the next part of their journey along the coast, but it was rough and starting to break up too. They stuck close to shore, and Togo picked his way carefully until they were back on solid ground. Next they had to cross Little McKinley Mountain (1,200 feet [370 m]), another of the toughest parts of the trail because of the many up-and-down ridges. The total elevation climbed in that section of over 8 miles (13 km) is 5,000 feet (1,500 m). After descending to the next roadhouse in Golovin, Seppala passed the serum to Charlie Olsen on February 1 at 3 pm.
On February 1, the number of cases in Nome rose to 28. The serum en route was sufficient to treat 30 people. With the powerful blizzard raging and winds of 80 mph (130 km/h), Welch ordered a stop to the relay until the storm passed, reasoning that a delay was better than the risk of losing it all. Messages were left at Solomon and Point Safety before the lines went dead.
Olsen was blown off the trail, and suffered severe frostbite in his hands while putting blankets on his dogs. The wind chill was −70 °F (−57 °C). He arrived at Bluff on February 1 at 7 pm in poor condition. Gunnar Kaasen waited until 10 pm for the storm to break, but it only got worse and the drifts would soon block the trail, so he departed into a headwind.Sled dog credit
There is much controversy surrounding Balto's role in the serum run and the statue in Central Park. A premier musher, Seppala ran 170 miles (270 km) east from Nome to just outside Shaktoolik, where he met the serum runner (to his surprise, since he had anticipated having to go all the way to Nulato and back alone), took the handoff, and returned another 91 miles (146 km), having run over 261 miles (420 km) across some of the most dangerous and treacherous parts of the run in total. He then handed the serum off to Charlie Olson. Olson carried it 25 miles (40 km) to Bluff where he turned it over to Gunnar Kaasen. Kaasen was supposed to hand off the serum to Rohn at Port Safety, but Rohn had gone to sleep and Kaasen decided to keep going to Nome. In all, Kaasen and Balto ran a total of 53 miles (85 km). Kaasen maintained that he decided to continue since there were no lights on in the cabin where Rohn was sleeping and he did not want to waste time, but many, including Rohn based on conversations the two men had before leaving Nome, and other decorated mushers in the surrounding area, thought his decision to not wake Rohn was motivated by a desire to grab the glory for himself and Balto.According to Togo's musher, Leonhard Seppala, who was also Balto's owner, Balto was a scrub freight dog that he left behind when he set out on the trip. He also asserted that Kaasen's lead dog was actually a dog named Fox, but that news agents of the time thought that Balto was a more newsworthy name. No record exists of Seppala ever having used Balto as a leader in runs or races prior to 1925, and Seppala himself stated Balto "was never in a winning team". Because the pictures and video of Kaasen and Balto taken in Nome were recreated hours after their arrival once the sun had risen, speculation still exists as to whether Balto's position as lead dog was genuine, or was staged or exaggerated for media purposes.The Central Park statue of Balto was modeled after Balto, but shows him wearing Togo's colors (awards). The inscription reads, "Dedicated to the indomitable spirit of the sled dogs that relayed antitoxin 600 miles over rough ice, across treacherous waters, through arctic blizzards, from Nenana to the relief of stricken Nome." In the last years of his life, Seppala was heartbroken by the way the credit had gone to Balto; in his mind, Togo was the real hero of the serum race. According to the National Park Service, in 1960 Seppala said: