Ice

4. Four boys age 7 to 11 drowned when a group of seven boys plunged through thin ice.

10. The catastrophe left four boys dead, their families crushed and rescue workers shaken following an afternoon of fighting a river of broken ice, the steep mud-covered bank and driving rain.

11. Dead are William Rodriguez, 11, of 292 Howard St.; Christopher Casado, 7, of 18 Jasper Court; Mackendy Constant, 8, of 7 Clinton St.; and Victor Baez, 9, 46 Bernard Ave.

12. Surviving the incident were Francis Spraus, 9, 14 School St.; Christopher's brother Ivan Casado, 9, 18 Jasper Court; Jaycob Morales, 10, 4 Winslow Place.

1. As seven boys finished their snack run from the Lawrence Boys & Girls Club to Hanson's Market yesterday afternoon, a sudden urge to slide around prompted 11-year-old William Rodriguez to dash for the serene expanse of river ice.

9. It was a playful impulse that ended with his plunge through the ice, setting off an ill-fated rescue attempt that deteriorated into a mass of desperate children clinging to each other in 35-degree water.

15. "Willie said he wanted to go down to the river, to slide on the Ice," Ivan said. “We tried to stop him.”

2. The ice was one to two inches thick where they ventured off the river bank. Four inches is considered the minimum to support more than one person, and river ice may not be safe even at that thickness because of currents and other factors.

5. Lawrence and Andover firefighters equipped with ice rescue suits arrived and after a search of the area where the boys went in, found the four remaining boys under the ice, 25 feet from shore in 15-20 feet of water.

18. "My legs started to get stiff, and I had a freezing headache," Francis said. "I was hanging on to Christopher, but he started to slip under. I tried holding on to his hand, but it was like he let go."

6. Because of the steep embankment, rescuers were forced to use ladders to bring the children up off the river to the waiting ambulances.

3. Police said the four dead boys were trapped under the ice at least 10 minutes.

8. It was the worst local Merrimack River tragedy in nearly a century.