I received the following e-mail last night from Professor Larry Shapiro, Chair of the Department at the University of Wisconsin at Madison:

I write to convey the news that Ellery Eells died today.  His health had
deteriorated over the past year and after entering a coma on Friday, his
organs failed and he died shortly thereafter.  He was 53 years old.  His
important work on probabilistic theories of causation and decision theory
made him a valued member of our philosophy of science group here at
Wisconsin.  He was a gentle, patient, and unassuming individual.  Those who
knew him will surely miss him.

There is some additional information about his career and well-known contributions to philosophy of science and decision theory here.  I will add a link to a memorial notice as soon as one becomes available.

UPDATE:  More warm remembrances from a colleague and a former student.