MINNEAPOLIS — It's official: Zach Sobiech is a rock star.

MINNEAPOLIS — It's official: Zach Sobiech is a rock star.

The Twin Cities teen — whose song "Clouds" went to No. 1 on iTunes just as he was about to be buried last week — now has the No. 1 single on Billboard's Digital Rock Songs chart as well as the No. 20 record on the big one, the Billboard 200 album chart.

"Clouds" is also expected to be in or near the top 10 for the general Hot 100 singles chart posting later Wednesday. Oh, and one more: He's also No. 1 on the folk albums chart, ranked over the likes of hot folkies Mumford & Sons and the Lumineers.

"The past few days have been very sad, exhausting and on the level of the fantastic all at once," said Scott Herold, founder of Rock the Cause, the St. Paul-based music nonprofit that is acting as Sobiech's record label.

"I've been updating Zach's family, saying, 'I hate to talk business at a time like this.' But their response is, 'No, this brings us happiness. This is what Zach wanted.' "

Proceeds from the single and album sales — which are at a higher percentage in this case thanks to the project's nonprofit status — are going to the Children's Cancer Research Fund in Sobiech's name. More than $100,000 was already raised between December and last week. Clearly, that was just the start.

Herold passed along the chart numbers this morning ahead of Billboard's official reports, which roll out every Wednesday based on the previous week's sales. "Clouds" was already rising in popularity when news broke last week of Sobiech's death May 20.

The Stillwater High School senior, who turned 18 on May 3, suffered from a rare form of cancer called osteosarcoma. When it was determined to be terminal, the budding singer-songwriter went about writing "Clouds" and other songs last year as a farewell to family and friends.

Originally recorded on his cell phone with an acoustic guitar, "Clouds" became a viral hit on YouTube last summer. It was then formally recorded with help from Rock the Cause and issued in December on a six-song EP, "Fix Me Up," released under the band name A Firm Handshake.

Thanks to media reports and widespread social media attention — though little radio play, which is a factor in Billboard charting — "Clouds" amassed 156,000 downloads in the week ended Sunday, according to Billboard, which ranked it at No. 7 on the digital songs chart. The full EP also sold 19,000 to rank at No. 20 on Billboard's album chart.

Because of the unique nature of the single, Billboard is still figuring out where "Clouds" will rank in the Hot 100 chart, according to its distribution company, the Orchard. Its No. 1 ranking on the Hot Rock Song chart puts him over the likes of such truly hot acts of the moment as fun., Imagine Dragons and Ed Sheeran.

Herold expects Sobiech's music in the current record-sales quarter to raise more than $125,000 for the Children's Cancer Research Fund — and counting.